My little sister hurt herself.

My sister is 15 and has a history of self harm. She relapsed yesterday after a year. My mom knows about it, but she won't get off her damn computer and stop working for 10 seconds to pay attention to her daughter. I understand she has to work, but I'm in a state of panic. I'm 20 and I don't exactly have the nurturing skills to help her, but apparently neither does my mom. She's already on medication for depression and anxiety. Mom keeps talking about new medicine and new doctors and I don't know how to help. I'm scared.