Maybe it is an alter who wants attention. Is it possible for you to ask them who is doing the SI and let that one know they don't have to do SI to get attention. Ask them what they want. It has helped me when I had one that hurt the body. I asked him why he was doing it and he told me that he was upset with me and some of the others because we did not acknowledge the times when we were young and he protected us. I apologized to him for not acknowledging him. I thanked him for being a protector. He stopped hurting us. He will still think about it and say for us to hurt us but that is more out of habit when he gets triggered. He is good to us now. And we are glad he is here