It can be trying to have friends with serious problems like cutting [a form of self-mutiliation where people will deliberately, repetitively, impulsively, and non-lethally harm themselves by carving words or pictures into their bodies, using implements such as razors, knives, paper clips, bobby pins, pens, scissors, combs, pieces of glass, or even their fingernails--see more resources here]. Sometimes helping them can really put you through a world full of hurt. There are a few things you might want to consider to see if you can get the situation under control for yourself and, perhaps, for your friend as well. First off, you might want to try to figure out why your friend may be cutting herself and, more importantly, encourage her to do the same. Cutting is generally a symptom of some larger problem with anxiety, anger or depression; getting to the root of that problem may eventually put an end to the cutting one. It also may be a positive thing for you to make it clearly known to your friend that what she is doing really disturbs you and that you are concerned about her. You friend might not be able to shake off the cutting as something frivolous when she sees how upset it is making you, and she might have some incentive to stop.

If after you talk to your friend and you see she's not heading toward some sort of self-induced resolution to the situation, you may want to convince her to seek other kinds of help, whether it is talking to a trusted adult or visiting a counselor. Should the situation escalate, you may want to think about speaking to a trusted adult directly about your friend's problems.

Ultimately, it is important to remember that you aren't responsible for living your friend's life or for making her decisions, no matter how much you love and care about her. Part of friendship is supporting someone when they are going through difficult times, but you aren't a therapist, and if you feel that this is simply too much of a strain for you, there's absolutely nothing wrong with giving yourself some distance from your friend.