Quoting ℐαzmчn:" Also we have talked to her doctor about this and he basically said to ignore it. I just can't see ignoring her if she's really trying to hurt herself though. "
Do you try talking to her calmly? I've realized when Christopher throws a tantrum I let him know I'll talk to him when he's calmed down, and ready to stop. Talking to him usually calms him down. I've read you're really supposed to ignore it, it only makes it worse.
Read this if you haven't already!