I was wondering when someone might mention this.
I've had it since I was nine, when I switched to public school (tough transition). I started by cutting pieces of my fingers off with a fiskers in class, just out of boredom, but then started biting any remaining bits of skin off. Then I switched to picking. Yeah, it sounds bizarre and creepy. I assure you I'm not completely psycho, I just have a thing for cutting things up (i.e. paper, veggies, carpet, hair) and tearing them. Maybe I should have been a hairdresser, but then again, after cutting my little playmate's hair so extensively when I was four that she had to be shaved bald, I think the shears are best left out of my hands.
I mostly do only my fingers, but sometimes my scalp, too. It's horrid. I wish I could stop, but it's so relaxing. Unfortunately, my hands are constantly bleeding. I don't feel pain too well, so that's not a problem. But it's so embarrassing when a classmate or potential love interest sees my poor hands for the first time.
Actually, it has gotten better in the last five or six years. I used to pick all the joints, around the nail and the entire underside of all my fingers. I still have some bad scarring from that, but now I stick mostly to the cuticle and up to the first joint on my ring fingers.
If anyone has any suggestions on how to stop, after fourteen years of picking, I'd try just about anything.