well for one, the first step in to recovery is actually admitting you do it, the second is admitting that you need help - so you have a great head start there! Its good that you seem like you really want to stop.

Why dont you see if you can list the reasons WHY you do it, and see if you can amend them and find a healthier replacement action for each one. for example, if you do it just to simply feel the pain, try the elastic band method for a while. Set yourself these changes one at a time, slowly changing each one, and if you replapse - forgive yourself and try again.

I dont know your MH history, but therapy could be a good help, or if you SI due to bad thoughts your GP might be able to prescribe you something for that.