I'll add, all of the people who had twitching that later developed into ___ had UMN symptoms + EMG abnormalities (fibs, pos sharp) at presentation in limbs most affected. But your timeframe to be 100% sure, if that extra .00001% is necessary for you, as it is me, is 7 months. But seriously, if you have a clean clinical and no UMN symptoms, try letting this go. If your neurologist says you're okay do your absolute best to trust him.
ShawnW is a great guy to talk to about this. He can confirm everything I've just said. He's also way better reassurance than I am. After all, I'm still in the throes of this horror too.
More, don't self-test. Skip that. Don't. You'll stress your muscles/tendons/whatever and you'll cause yourself more grief stressing over sore muscles and painful joints. And don't set your jaw. Mine's painfully sore from anxious tension and you'll begin believing it's bulbar onset. It isn't bulbar onset. You hold tension in your jaw and anxiety will affect your speech if you begin thinking you have bulbar. Same is applicable to limbs. Try not to hold tension.
Just trying to anticipate 'symptoms' you'll later experience. Critically, rationally analyze what you're going through and if there's another, more likely, more logical explanation, it's that. It's always that.
Fourth edit, don't look for atrophy. Your body is asymmetric. You don't know what you're looking for. You would have clinical weakness and extreme deficit before atrophy. You will find pits, scars, holes, dents, everything. Unless you're REALLY weak in that limb, ignore it. I have a dent in my forearm. No idea what it is. I don't grow hair there either. Looks like a circulation issue or a scar. At first I freaked out and thought I was dying. It wasn't atrophy. One side will be bigger than the other. Also not atrophy.
Fifth, if you don't take the advise of this board and go out and consult doctor Google, the dents in your tongue are tooth-marks. Everyone has them. If you go further and find out how to examine yourself, not everyone is very coordinated with their tongue. I can't move mine up and down very well or fast. Well, actually, I can now, after having practiced so much by self-testing. But a month ago I couldn't. Means nothing. Don't think about swallowing or you will develop problems swallowing. Don't focus on your saliva or you will develop excess. Don't focus on your breathing or you will hyperventilate. By the way, hyperventilating can cause twitching. Don't focus on twitching either. You will twitch more. Your body is a big-fat liar. Reject everything it tells you with regard to ___.