Helping a friend remember a title of a movie

Hey there ladies, and gents,

I’m trying to help a friend remember a name of a movie. She doesn’t remember much of it, but for whatever reason, she suddenly had a memory of it and wants to find it. It’s a ‘90’s movie she thinks. The movie starts out with a young blonde teen in her parents bathtub and has dates and markings on her forearms in permanent marker. She later goes to live with her grandmother, who has something similar.