This is awkward, because the right advice would be to tell your GP about it, and so on, but at the same time, i know that i wouldn't mention it to my GP if he asked me.
It sort of depends really. I'm really not 100% sure how to answer that.
I, personally, don't think much can come of it. the only way to stop self harming, is to do it off your own back. (that's my opinion anyway)
Maybe you're better off dealing with the issues causing it first. That should ensure you won't need to turn to the blade as often, and the attempts at stopping would be more successful.

tc, Kelly x