Is it normal that i have to constantly bite the insides of my mouth?

I do this too. I hate it because it looks really weird and I don't usually notice when I'm doing it.

there are many things like this that can happen when someone is thinking. my ex would constantly stick her tongue in and out in and out when she was thinking.
i bite the insides of my cheeks too, but not because i'm thinking, i just get an uncontrollable urge to bite the loose skin off.

I do this too, I even started doing it at around the same age as you. I seem to do it more when I'm either stressed or bored. I stop if it starts to hurt (it rarely reaches this point), so I think, at least in my case, it's harmless. If it doesn't negatively impact your life, leave it be. Just remember to not do it public, unless you don't mind people thinking you're weird.

Ok I don't do it but my ex hubby does it and actually takes a bent finger at the knuckle to get a better grip on some meat. And considered inventing a knuckle like tool so he could get different angles that his arm was not letting him achieve. Lol. Oh but if any of you who do this would be interested we will try to accommodate you or he will just message me cause he owes me $$$$. Wow who knew?

I've been doing this for awhile now and then I came across this.. XD yeah its normal. I chew the skin off my lips too.

Kind of a different version of grinding your teeth.

Sounds like a bad habit.

Sounds kinda freaky to me be careful you don't chew your mouth away.

You'd look like some kinda real life zombie and someone might bash in your skull just to be on the safe saide.