It happens to me too. Your not alone.

Where's doc bastard?!?

You need to go to an orthdantist they specialize on the jaw and mouth rather then just teeth and a doctor is just no help

I do it because I have TMJ and my jaws don't line up all of the time. See an oral surgeon or an orthodontist. They can check your jaw joints and help you.

Sometimes I bite my inner lip, really hard and it leaves a whole for a long time, it's like an ulcer but always hurts :(

I always bite my cheeks on purpose it's a bad habit but it doesn't hurt anymore.

Same with me, OP. My teeth are closer to my right cheek so it's regularly rubbed/bitten to the point I can get black blood blisters on them.

Ouchie! I do that too and sometimes I even feel like that shock of pain is going to make me pass out!

I'm sorry OP :( that happens to me too ever since my wisdom teeth came out.

or maybe eat slower it happens to me when I'm really chowin down