shes doing it for attention. Deny her the attn, and contact a shrink for her or something. There is no way you should have to deal with the added stress and worries becuase of her selfishness. Life sucks at times, you dont deal with it buy slicing yourself up.
I know someone that started doing that, and I told her that if she continued to do that, she would lose the only person that was willing to listen to her whine about life suckage and try to pull her ashore. She thought long and hard, and hasnt self-mutilated herself to this day.