My Friend Is Cutting Herself, What Do I Do?

You need to talk to her alone and try to convince her not to do that. She should believe in herself and should not take her life. If need arises you should talk to her parents or take her to a doctor.

Being an "emo" has to do with social identity, not self destructive behavior. I suggest you talk to her in a setting where she is comfortable. Let her know that you don't like seeing her hurt herself and that you are there to talk and give her support. That's about the best you can do, but I also suggest that she see a therapist. Getting her to see a psychologist or a psychiatrist may be difficult though. With appropriate therapy and/or medication she will likely be able to work through this difficult period in her life.

Reassure the person and try to get them to seek professional assistance, in most instances self harm is a cry for help.