I don't know what to do but i'm confused?

About a week ago my friend and i were watching this movie on tv called "13." the girl in the movie "cut herself"...u know like self mutilation. anyway, a few days ago my friend came up to me telling me she was really depressed (the same friend i watched this movie with.) I tried to comfort her and ask her why and she just told me she was "sad all the time." It was interesting to me because before we watched "13" she was normally pretty happy and a then after watching a movie about a depressed teen she became in her words...miserable. However i believed her and didn't think she was being a fake idiot lol but then today in homeroom she asked me to come to the bathroom with her. She told me that she had been "cutting herself" for six months and that she wanted me to help. She showed me her cuts but they were new and they weren't deep..they werent really cuts...just scratches. anyway, u could tell they were new and there def. wasn't scarring or any implication that she had cut before that.