i think i have a problem....

ive been biting my nails and picking on the skin around them, almost my whole life. im 21 years old and i never thought i had a problem until now. i know some places says it might be because of stress. but i do it all the time, even at my most happiest. ive always thought its just a bad habit. my mom used to pick on her lips a lot when i was younger, i started to do it too, but i stopped. with my hands its just different. if im on the fone n im trying to 'fix' my nails or the skin around them, i will put the person on hold while i finish. its this weird impulse that i cant seem to control. as we speak im picking on my cuticles. i pick on them until they bleed n my finger is purple n swollen. i do it a lot in public and i wonder what people think of me when they constantly see me picking my nails. i dont know how to stop it, i dont think my brain wants too, because i just think hey im not hurting anyone and im not causing any serious damage to myself either, so why bother stopping. the skin around my nails have been re made so much, i doubt i have a single original cell thats lasted more than a week.