I don't know much about cutting, but on the relationship front...if he seems like the one or a potential one I'd advise telling him. He will find out at some point. If you talk to him about it before that and allow him to ask questions, really tell him what it is about you won't feel you have to hide it from him.

You'll also know if he is willing to walk beside you through the worst.

There are those that will. There are people that accept and love an entire person, not just the pretty on the surface.

I wish you the best.