I was doing this as well, and ended up having all of my torso covered in scars (I am still insecure of taking off my shirt with other people next to me because of this). One day I realized it had to be stopped, so I abstained from it and it hurt really bad. I was always thinking of cutting and how much pleasure it causes me. Fortunately, I made it until the end of it and now I don't have such issues anymore.