Have you ever heard of the butterfly project?
When you feel like you want to cut, take a marker or pen and draw a butterfly wherever the self-harm occurs and name the butterfly after a loved one, or someone that really wants you to get better. If you cut before the butterfly is gone, it dies. if you don't cut, it lives.
I believe it is a positive way of working with self harm, though personally I have never properly cut I used to scratch away at the skin on my arms to 'punish' myself but the butterfly project helped a lot. It made me think about others and not just my own pain.I really hope this will help you,
peace and love x