okay sorry for the very long post. here are a couple helpful sites on self-injury, on methods to stop, how to tell others about it, etc. :
http://www.palace.net/~llama/psych/fself.html
http://www.angelfire.com/bc3/secondchance/
http://www.depressionforums.org/forums (forum for depression, but there is a small section on self-injury too)
i've been doing self-injury since i was about 12 (i am 20 now).
my reasons have changed drastically over the years, i think. probably for several years since i first began it was because i was severely depressed and cutting was a distraction from general feeling emotional pain, it was done as a "punishment" i felt i deserved if i did something like binge eating, it was done to distract myself from certain negative thoughts like memories of some embarrassing situation i was trying to forget, i liked the look of it/after results and it was calming if i was depressed, etc.
i think in the past year it's changed a lot though, and i've just been doing it when i haven't exactly felt depressed, but more so just to get some cheap brief release of endorphins, to enhance a high i was already experiencing, or because i genuinely think it looks aesthetically pleasing, like a form of art.
lately it's been quite out of control though, and instead of keeping it to small hidden area of my body i end up doing way more damage than intended. it's just looking ridiculous, and probably also because it looks so messy, i don't find it as beautiful. i will also occaisonally do it if i am very angry and agitated, and there are few other ways i can effectively get that away.. at least none i have figured out, the others just being taking a benzo or drinking alcohol.
i find what also makes it such an easy habit to get dependant on is because there aren't as many negative aspects, compared to smoking cigarettes, or drinking for example. sometimes i lose control and cut too deep, and it freaks me out. that happened last time and i decided it was time to try to stop. (oh wait.. i did it yesterday lol. i guess i forget.)
i've definitely regretted starting in the past, at such a young age. i used to cut my arms mostly since i couldn't stand to look at my stomach or legs since i thought they looked fat at the time, although the torso/thighs are the only areas i cut now. that meant that i would have either my arms were covered in cuts, or scars once they healed, since i could never do just a few. i think i counted once them like a couple years ago and stopped at 100, but now there are more. :/
since i was so afraid of people noticing, i'd basically wear long sleeves every single day of the year, even in the humid 35degree weather. one day i realized it was stupid and i should just accept that they will always be there and started wearing short sleeves, which feels incredibly freeing (the very first day i did that, a friend commented in a patronizing tone that made me feel like a freak, and ironically it was while in was in the hospital and this friend also had the same mental illness as i).