Dd told me last night her friend has been scraping her arm, punching a door until her knuckles bruised (at her home). Dd also took a pen off this dc as she was poking herself with it to hurt her arm (in front of my dd). I have not met her but dd is very fond of her. From what she has told dd, she has a troubled home life and is now living with grandparents. I don't want to cause problems so not sure what to do...