Mouth/lip picking?

I grab a little piece of skin from the inside of my mouth with my teeth and tear it off. Does any one else do this too? Sometimes I grab big chunks and then the next day it hurts bad. They bleed too, not for very long though. I do it a t school a lot. Silent, unlike nails. (when I pick my nails there is a slight ticking sound, nails against nails) I can't pick my face at school, I'd be walking around with a bloody face It makes my mouth look like I ate something sour, but it's okay. Also when my lips are chapped and peel-able, I bite them and peel the skin off with my teeth. I only do this in the comfort of my home because it makes me look stupid at school. They bleed of course. Also, one last thing I just thought of. Do you guys pick your nose? I've been doing that since I was 4. The only time I've ever stopped (for about a week and a half) is when the swine flu was going around 3 yrs ago. I pick my nose when I'm sick with a cold or a cough or whatever. I don't care. I only do it at night, in bed. I even do it at sleepovers when I think everyones asleep. My sister teases me "oh I saw you! I saw you!" of course she doesnt do this sort of thing. And I let the teasing slide, but my cover was almost blown. Please comment! Thank you!