My daughter went thru a period of SI. She stopped on her own, in no small part due to her own faith, and only told us about it after talking it over with her youth pastor. It sounds like you might not have that trusting kind of relationship with a pastor, but I think that having someone like that in your corner when you tell them about it might be helpful, especially if you feel they're prone to ignore "professionals".

Of course, they might surprise you.