I blew it…

You didn’t “blow it” and I seriously doubt he’d be happier if you were gone. When I cut myself, most people didn’t know how to react. Especially my parents, it’s a very scary thought that someone you love is hurting themselves and there’s not anything you can do about it. People react badly, give him some time and explain why you did what you did. The deep down emotional part that triggers it and maybe he’ll be a little more understanding. We all fall down, don’t let this keep you there.