Friend is suffering to me, parents aren't helping?

You sound like a really good friend and your friend is suffering from extreme depression and the cutting is also very dangerous. It is extremely neglectful of her parents to ignore her cries for help. She does need professional help. Of course there is no since in talking to her parents so you need to talk to a teacher that you trust or your school counselor. Her parents will be forced to get her help. Without your help it could get much worse. I understand this is a load on you but you will feel so much better when you get it off of your mind and know that you have done something good for her. This is something that can't be ignored.