Most Helpful Girl
Self harmers are very touchy... Give her her space. The best thing you can do is make sure she knows you're there. Or you can let her go.
Most Helpful Guy
You can't feel responsible for everyone in your life and bare the wieight of everyone's decisions in life on your shoulders.
You said she was like that before... so she should have family and other friends to help her.
You being in her face... may just make things worse. Walk away and don't try to help... let her friends and family network help her.