How can I help my girlfriend?

She has been going through a lot of stress lately and she got to the point where she started cutting her arms again. I tell her to throw out the blades she has, and go to her parents and get them to help, but she refused to throw them out cause "they make her feel safe" and she won't go to her parents because they have a habit of saying they will do something for her like get her glasses, and they never follow through. The only thing i have on her is I will make us end and get her nurse and doctors (my mom and people I known since I was 2) to do something. I just don't want to get to that point because most already think her family should go to a loony bin. Any help