It's 9.50am and I'm already bored out of my mind; maybe I should get a job or something. I'm back at my parents' house, and this time it's permanent. I had one last trip to London at the weekend, but now I'm in the parental home for good. My last rent cheque on my flat ran out yesterday. There's no pretending anymore: I live here now.

On Friday morning I stood on the platform at Dumfries station waiting for my train. Behind me were two blokes watching a happy slapping on a mobile phone. Typical Dumfries, I thought, even when it comes to anti-social behaviour they're months behind the rest of the country. One of them looked in his fifties, moustache, grey hair; the other was ginger, half his companion's height and age. "Look at this, gang ay bams gie this wee boy a doing," barked the older one gruffly. His young friend peered over his shoulder: "Ha ha that's a sin so it is ha ha perr wee gadge ha ha." This went on all the way until I changed at Carlisle.

As I walked from the tube station to my soon-to-be-vacated-flat I felt as though I had been away longer than five nights, like I was walking streets I left behind a long time ago. Maybe I'd spent the past week getting a bit too used to being at home. By the time I walked into the Camden pub which hosted my leaving do the following night, however, it was the opposite sensation: like my life over the past few years ago was being represented by friends from each constituent element of it. It was fantastic, all these great people there and I didn't have to buy a pint all night. One of my flatmates said it was like I'd had two birthdays this year, and he was right. My present tally for the weekend included a bottle of whiskey (Auchentoshan), a colouring book, a bumper set of word puzzles and the loan of series one and two of the West Wing on DVD. Everything I could want, really.

We went onto this club on the Chalk Farm Road and the playlist was just right for the evening: lots of indie rubbish ideal for jumping up and down and singing along. With all my friends there, I don't think I've been so happy, so lost in the music and the moment, for ages. I took lots of pictures, and as I looked back on a photo of myself on the rear of the camera I thought, maybe this is the last time I'll come to a place like this and not look like a complete freak. I pushed the thought to the mind and flailed about a bit more.

Monday was when I left for good. My posters I had kept on the wall until the last minute, after I had sent the rest of my stuff up the road, so it was finally time to take them down. I put what I had left into a few bags and lugged it down the Euston; on the way I needed to drop some of it off in town and enlisted a friend to help. We parted company at Great Portland Street, hugged before going in opposite directions. And then that was it, I had left everyone behind.

At the station I saw my train, the Virgin intercity service to Glasgow. That's where I'm going, I thought, but not today: I've got a week's grace first. I hopped off just before the border, waiting for a commuter service to take me to my new and old home.

They say it takes fewer muscles to smile than it does to frown. Except for me there's soon not going to be much of a difference, at least on the right of my head. I'm looking at losing the use of all my facial muscles on that side, so if I've got my head turned a certain way you won't be able to tell if I'm elated or depressed. Which I imagine will be extremely handy when I'm playing poker.

The website of the British Acoustic Neuroma Association (link above) has just been updated, and the members-only section (here's a bit of insider goss for you non-AN sufferers) carries pictures of people's fizzugs post-op. Here's a couple:

In both these shots the subjects are saying cheese for the camera, just on the one side. The bloke on top carries it off quite well, I reckon, sporting a wry expression suggesting a dry, understated wit. I have to say that I'm impressed by his adaptability. I'm going to have to change my sense of humour and start finding Rory Bremner funny.

The ability to smile and use thereof is an expression of your sense of self. Maybe you go around grinning all time because you're such a happy sort; perhaps you ration those dimples on your cheeks for when you are truly elated. It could be that you work in the service sector and have to bear your teeth at all times, and revel in sulking when you get home. Or, alternatively you use the expression as a means of defiance over adversity. As Shakespeare says in Othello, the robbed that smiles steals something from the thief. I'm going to have to come up with another way of getting my own back if I'm ever mugged.

"When you're smiling," croaked Louis Armstrong, "the whole world smiles with you." Apart from all the post-op acoustic neuroma survivors, he might have added. We can guess that Leornardo Da Vinci would have excluded the likes of me from being the model in his best-known work. Mind you, my teeth were always a bit too wonky to earn me matinee idol status, so it's not like I'm losing out on becoming the next Cary Grant.

But for some of my fellow sufferers, this is the hardest aspect of adjusting to life after AN, as distinct from disfigurement per se. Here's an anonymous quote from a study of people recovering from surgery, as published in the latest issue of BANA's magazine Headline News:

 "I have emotionally found it extremely difficult that I have lost my smile. I used to be a very smiley person."

Perhaps as a result of this, the Association has decided that defiance is the best coping mechanism. Members can buy a range of pens and stickers featuring an Acid House-style face, with the mouth turning upwards at one side only. It carries the slogan: I'm all smiles inside.

So does that mean I am too? That all depends on how the operation goes on Tuesday (God, it's not far off now, is it?). The hard bit isn't getting the tumour out, it's preserving the nerves that control the facial muscles. If they sever it, that's me; they can try using some tissue from the mouth to repair it, but I won't be left entirely symmetrical. If it stays intact, I'll probably carry on looking as I do for a couple of weeks. Then, because the tumour has distorted the nerve and it hates flopping back into place, my right side will temporarily palsy. By "temporarily" I mean anything up to two years, and in then end the face might even function at 80 per cent capacity. There are other side effects of this process (the eye refusing to close sounds the most gruesome). But I would take looking relatively normal by 28, not a shadow of a doubt. 

In the short-to-medium term, anyway, I'm going to have to get used to talking out of the side of my mouth like Dick Cheney. Right-wing warmongering draft-dodgers are not generally my idea of style icons. But look on the bright side, I won't have to use so many muscles.

The incomparable Charlie Brooker admits in today's Guardian he once told a girlfriend he was deaf in one ear as an excuse for not having listened to what she'd been saying. Unfortunately, he had to keep up the pretence for the six further years they went out together. The article made me laugh so much that Irn Bru came out of my nose.

Problem is, this throws up a whole load of difficulties for me. If I end up going out with a liberal, well-meaning leftwing girl who's read the piece I've now got a whole load of trust issues to surmount.

Eyeballs! They've always made me a bit squeamish. Maybe it's because they're such soft, squishy, vulnerable entities in the midst of a mass of tough bone, but the thought of injuring or even interfering with them has always made me squirm. I always, always look away from TV footage of eye surgery, blink furiously when someone else gets a bit of grit trapped under one of their lids and chew my knuckles when reading about some poor unfortunate's peepers suffering a cut or, like those of Oedipus, worse. Just imagine all the terrible, painful things that could happen to your baby blues. Urgh! Actually, don't.

Well, thanks to my tumour I'm going to have to confront this phobia directly. One of the many side-effects of the operation is that afterwards I might not be able to blink. You see, one of the nerves adjacent to Ally controls the eye mechanism; so whether temporary or permanent, it is likely that I'm not going to be able to close my right eye. If it's a window to my soul, it's going to have the curtains left open all day with the aftermath of a particularly messy party on display for all the neighbours.

The main problem here is that blinking moisturises the surface, spreading liquid across it. Without this it can dry out in as little as ten seconds, leaving a red, raw irritable cornea on display. Even though the tear ducts will be producing industrial quantities to soothe the irritation, without the lids working they won't have much effect; neither too will applying drops. There is one solution: rub a medicinal gel across it. By hand.

That's right, you heard me correctly. I'm going to actually have to touch my own eyeball. With my finger. I'm shuddering as I write this. Those of you who wear contact lenses probably won't find this a big deal, but to me it's just a sliver away from the infamous scene in Bunel's Un Chien Andalou.

And it gets worse. If the nerve is cut and my eye is knackered for good, there are a couple of gruesome-sounding ways of dealing with it in the long term. One is to insert a gold weight into the upper eyelid to help it blink. If this doesn't work, the eye surgeon can perform a procedure called a tarsorrhaphy. This involves stitching the lids together, either temporarily or permanently. The thought of a needle going anywhere near my irises makes me screw up my face like Mary Whitehouse on the set of Michael Winterbottom's 9 Songs. Excuse me while I make a cup of tea and wander around the room a bit.

The one upside to all this comes from the fact that I've recently been diagnosed as short-sighted, although I'm waiting until after the op to get glasses in case the tumour affects my prescription. I always thought contacts were out of the question. But if my eye goes back to normal, I might be entirely blase about the thought of sticking things on top of my pupils. Think of it as aversion therapy; it's one way of getting over being a big girl's blouse.

No more fresh air for me, then. I spent the last few days taking advantage of the lull in the rain to have a final pop at the great outdoors. For the next wee while I'm going to have to become a bit of a recluse, like Kate Bush with less elaborate costumes, so I wanted to get outside the house for a bit. I wandered the wilderness of Dumfries and Galloway, the wind buffeting my cheeks and ruffling my hair, except when I was in the pub (i.e. most of the time). The locations graced with my anoraked presence, for all you rambling fans out there, included the road from Kipford to Rockcliffe then Castle Point, and the village of Moniaive (the one vaguely glamourous location in south west Scotland - Franz Ferdinand's most recent album was recorded there). Today I walked along the cliffs around Auchencairn, which you can see above. I swear that two minutes after I got back in home through the door tonight it started lashing down. And so, the weather signaled, my outdoor were adventures over.

Obviously, I'll be in hospital for the next couple of weeks. When I come out I won't have enough energy to climb the stairs more than a couple of times a day, and my balance will be that of a one-legged drunk trying to stand up on a bouncy castle wearing a rollerskate. And even when these improve, it's more than likely that my knackered eye will prevent me going anywhere with a strong wind.

This is all a shame, because I've got a bit of a guilty secret: I really like walking. Not just strolling-down-the-road-to-the-shops walking, but proper walking: Helly Hansen coat, sturdy boots, Kendal Mint Cake in the pocket. I don't know how I've exercise self-restraint and not grow a beard; as it is I refuse to drink lager, for God's sake. One of my proudest moments was when I climbed Croagh Patrick, a mammoth 2500-foot mountain on the west coast of Ireland (you can see a photo of me at the peak looking at once triumphant and also desperate not to vomit with fatigue here). My moment of victory at scaling its near-vertical ascents was shattered when I remembered it is regularly scaled by elderly catholic pilgrims on their way to cash their pension books.

Today I looked at the crashing waves and the golden leaves and thought about how I won't be doing this again for a bit. It didn't help that the scenery was fantastic, and it was a perfect autumn day: it's funny how what is basically a process of decay can look so stunning. And a moment of self-pity started to set in, as I realised the rugged coastal path was effectively leading me to my bed. The only time I'll be surveying vistas like this for a while will be on the off-chance that they feature an Area of Outstanding Natural Beauty on Songs of Praise.

But then I remembered that I was being a self-pitying twat, and a strong, firm inner voice barked into my good ear: "Stop your moping, lad. A few months in the kip is something lots of us would give our right ball for. So let's hear no more wingeing. Go on, get stuck into that Kendal Mint Cake."

It is true, though. I am very fortunate not to be incapacitated in the summer. Can you imagine how much worse it would be to end up bed-bound as the sun shone brightly, as I watched pretty girls float past the window in flowery dresses and listened to tales of friends having a right old beano at the music festivals? If you can't, I'll tell you: it'd be hell. I'd rather remove the tumour myself than go through that.

As it is, I get it quite easy. After all, we're in for what forecasters believe will be one of the coldest winter in a decade. While you're all outside freezing in the sub-zero temperatures and falling over in the slush on your way to work, I'll be in the warm drinking cocoa and watching Children's BBC. Ha! Who's incapacitated now? Every cloud has a silver lining, they say, even the big black ones which are right now tipping rain onto my roof.

They say it's going to rain today, that the temperature is going to take a dive. I couldn't care less; I'm going into hospital. And whatever else might befall me in there, I'll be safe indoors from the icy sting of the wind. It's winter now, and time to hibernate.

If you're reading this just after getting into work, I'll be on the 8.50am train to Glasgow. Or should you check my diary about noon I'll be arriving at the Southern General, getting shown to my bed and unpacking my belongings. Maybe you've left it until you're about to go home, about 5pm; then, an anaesthetist will be preparing to put me under the next day. And if you're looking at it at 10pm the nurses will just be offering me a wee something to help me sleep, and I'll be accepting it.

Everything I have written until now has been speculation, a combination of educated guesswork and a slightly morbid revel in worst-case scenarios. Well, the time for that is over. The array of possibles and probables are about to turn into actuals and definites. We'll soon find out what will happen to me, and you there will be no more ifs and maybes in my case.

There's a bag sitting in the hall. No change of clothes, just pyjamas. I've stocked up on books, but the nurses advised me that my concentration might be too far shot to get anything out of them; they recommended CDs. I've packed the familiar (Teenage Fanclub and the Smiths; Revolver and Abbey Road by the Beatles) and the soothing (Belle and Sebastian, Felt, Dylan in his less abrasive moments). My own personal easy-listening hospital radio.

Tomorrow they'll wake me up about 6.30am. Within the hour I'll be under general anaesthetic and out of it until lunchtime on Wednesday. And what they do between, roughly, 8am and 9pm, could define the rest of my life. Who knows? I'm just keeping my fingers crossed the surgeons keep away from their local pubs tonight.

How am I feeling? Scared? No, I've been over what could happen too many times for it to hold any fear for me. But what is taking hold is the uncertainty; not knowing what's going to happen. You can try to exercise some control over these situations by preparing yourself. I can't do that right now. But, if nothing else, I'll know where I stand very soon.

You won't hear from me for about a fortnight. I don't think the NHS offers broadband on most neurology ward. But I will try to document the coming period, even if the results are sketchy ("Wednesday: Ugghhhhhhhhhhhhhhhh. Thursday: That... morphine's... lovely..."). But if this journal is to fulfill any purpose I need to make a stab at documenting what is, after all, the critical passage of this story. I'm taking in a notebook and a dictaphone; anything I get down that makes sense afterwards I'll post up here in due course.

You're getting no profound aphorisms from me. I'm not on my deathbed, after all, and, in the words of Mr Marx, "Last words are for the fools who haven't said enough." I have no intention of inviting nemesis by going down that road. I have tried, with however much success, to avoid cliche throughout this diary. The temptation is to look upon the growth as a manifestation of some kind of inner turmoil which is about to be excised, or of my own sins and tumours of the soul which will be cut out for good. Catharsis, a real catholic way to make sense of the experience. I'm not going to do that, beyond make flippant comparisons with footballers, because I know whatever flaws and demons I carry with me will still be there when the operation is over. But I know they will take from me more than a lump of cells. I've never even remotely gone through anything like this before; I suppose I'm going to be changed forever. Hopefully something will be added too.

I can see last night's rain spattered across the road, but so far the forecast is wrong. The sky is clear, with a streak of pink in the clouds. The leaves haven't all fallen, not yet; in the half-light I can already make out the browns and golds and ambers on the trees. The sun is rising behind me and right now it is hitting the green fertile hills of Galloway to my west. It's going to be a beautiful day.

Well, as you can see, I'm not dead. While this might detract from this blog's dramatic impact, it's obviously pretty good news for me.

The last couple of weeks have been a bit of a blur, which I suppose is a fairly predictable side-effect of having strangers fiddle around inside your head for 13 hours. But the upshot of it all is this: I'm here, and in good shape. I look rather weird, of course. The right half of my face doesn't work and I can't close my eye on that side. I have the haircut of a far-right extremist and a huge scar around my temple just to complete the image. My sense of balance being shot, my best attempt at walking consists of shuffling like a Chelsea pensioner on his way to Ladbrokes.

None of this bothers me too much. Because just before they stitched me back up, the surgeons checked my facial nerve and it seemed, though bruised and swollen, to be intact. So my chances of looking normal again are very good. I've also managed so far to avoid the other worst-case scenarios: losing control of my breathing, picking up tinnitus, suffering from brain damage or worse.

As it stands my symptoms are not all that debililitating. I'm knackered all the time, but then if you work in any kind of stressfull occupation then you probably are too. I find it hard to concentrate on anything for any length of time, and this isn't just to do with me being a lazy sod. My skull does ache around the wound, but I've been prescribed a battery of painkillers to keep this at bay. And my irritable right eye demands constant attention, like a spoilt toddler, and probably occupies more of my waking thoughts than anything else.

But still. I'm here, sitting up at the computer and fending for myself. Over the next couple of days I'll fill you in on my time in hospital and let you know how the move back home is going. In the meantime, though, I'd like to thank everyone who sent cards, flowers, and messages of support and gifts over the last few weeks: it all meant a lot and I will get round to replying personally in time. And for all that I've come out of this experience looking like I've had an accident with a threshing machine and feeling fairly similar, I'm very, very glad to be here; I'm also very glad you're all here too.