As much as I want to say yes, the answer is no no no. If you give in now, even for the right reasons, it'll only get worse and be harder to quit. Have you considered talking to your therapist about ideas/options to help deal with the added stress of getting to a better place. If you do need an extra something to deal with temporary stress instead of SI I'd definitely recommend holding ice or sticking your hand in ice water, but anything more permanent is just going to lead to more shame and guilt and probably make it even harder to make friends. I know when I would cut it was harder to make new friends because I was always scared of them finding out, or judging and not wanting to be my friend. And if I didn't tell them then I felt like they weren't liking me for me because they didn't even really know me, just knew who I was pretending to be.