How to control self harm compulsions?

I kniow how you feel, although you don't want to hurt yourself, you feel asif you have to! Almost like it's to punish youself. What I did was buy a punch bag, after a while I became adicted to boxing/skipping and different kinds of exersize. Whenever I feel the need to cut, I go for a walk or do something energetic to take my mind offf of it, hope I helped x