I told my former T I do have an eating disorder and I'm unwilling to give it up. Could you say that to your T about self injury? My T just smiled when I said that (probablya because I admitted I had an ED) and never mentioned it again unless I did. I did have to agree with her that if I went without food or water for more than 2 days I'd go to the crisis center. Every now and then she'd say "still eating x amount? " I'd say yes or no and that'd be the my oend of it. As my other disorders improved so did my ED.

This maybe the case for you with SI but you have to tell your t that yes you engage in SI, no you're not going to talk about it, and you have no plans to give it up.