I have intrusive thoughts too, although not of self-harm. We aren't responible of this thoughts, it's OCD that makes us have them, so you don't have to worry that you wouldn't have them if you didn't want. These aren't like other thoughts. At the beginning it's difficult to igore them, but it's possible...I tried and now I still have them sometimes, but I don't think anymore that it's my fault, and this make them to be less annoying. I suggest you to continue trying. I don't know if it's possible to completely stop having these thoughts (I'd like to know it), but the important thing is that we aren't distressed for them! I hope that you sugged in this. If you continue with your therapy and with the support group I believe that you can do it. If you want to talk I'm here!