I'd throw this one back to the school to a certain extent. Yes, it is your job to keep an eye on y our daughter but you'r ealready doing that, it's how you were able to alert them to this. You alerted THEM because you had a heads' up on this. Your increased vigilance wouldn't have made much difference here, I don't think. What more can you do?
You need their involvement too, this is a team approach. Ask them to maintain their vigilance also, thank them for following through on your alert but let them know that while you will continue to do what you can, as you have been doing, you will still need their help too at similar times. She is a hard case and you're having difficulty being taken seriously with your concerns.
Re the face scratching - document. It's one of the many reasons I bless digital cameras. Stand her in the bathroom with the lights glaring, sans make-up, and take a photo. Scratches heal. The photo is permanent evidence.
And someone else said,
And lock up all razors at home. Switch her to Nair!!
In my book, even Nair would be out. She either goes native, or uses an epilator. If she abuses the epilator, then she goes native. I wouldn't trust her with hot wax, either.
Actually, if she's cutting and is trying to do this in order to have an inner pain match to outer damage or the feeling of it - cold wax might be an option. Similarly, the pain of using an epilator might be helpful for her. But if it's the visual she's after, then give her a red pen and let her draw on herself. Aim for water-based so it will wash off and come out of clothing in the wash.
But skip the Nair.
Marg