lol, I know what you mean. Your problem is a lot less serious than you think. I never did anything social at school, I was by no means a nerd but I was and still am a AFC. Although im learning fast
Basically i've come to university and I don't care about making a fool out of myself so much etc. Your problem is probably that you can smile and it will probably look fine but you are worried about your display picture looking stupid. Just take another picture and go with it, hell I look terrible in photos when im drunk on facebook. Of course you can smile just take a picture and go with it.