have any of you ever known anyone to cut their self on purpose?
yes...it's typically their response to stressful situations when they feel out of control. If he did it as a teen and hasn't done it until recently, then he's facing a severe stressor right now and probably needs professional help. You might want to talk to him, in private. Tell you want to make sure that everything is OK with him and ask him point blank if he needs help or is considering hurting himself further. If you're not sure how to handle and your company has EAP, call them and ask them how to handle.