He cut himself for me?

It shows that he's in need of serious psychological help, from a licensed, trained professional. Harming yourself (or threatening to harm others) is never appropriate, no matter the depth of your feelings, and does not indicate a mature love. You should stay away from this nut job, and strongly encourage him (or his parent/guardian) to get the help that he needs. You don't want to end up as a tragic story on your local news...