I do agree that one way is to get help and the right help. If a therapist is not working out try and find another. For me I worked my way through and dont really do it anymore. I did have one blip recently but it was not like when I have cut myself, which was always in someway ritualistic. Here I hit my hand w a knife, I did not know which side I had hit with and was surprised to see blood. I do hit walls sometimes these days and well tht was a variation of that.
But the actual cutting ritual for me needed certain set requirements and one was not the rage I felt when I recently hit my hand w a knife (fool I am!) So when I was tempted a few months ago I did not go ahead. I dont know if this helps at all but some people find a way through and ok I am not perfect I do hit walls at times which is another form of self-injury but I am better than I was.
"I will not fear. Fear is the Mind-killer. Fear is the little death that causes total obliteration. I will face my fear. I will permit it to pass over me and through me. Where it has gone there will be nothing. Only I will remain"