My daughter was very "different" and withdrawn when she was actively self harming. Once we found out about it we were able to see the signs. It didn't mean that we could divert her from this or even talk about it. So I just gritted my teeth and tried to be dad and took every chance to chat, even the pedestrian stuff, so it was a habit and hoped that we could keep talking rather than the silence we'd had so many times. It felt bad and we felt very helpless but there was nothing we could do.
After a while she stopped and we finally realised that. A lot of the history and what she actually did came out at an interview with a psychologist she was seeing. We were invited in for a chat at the end of the session and found out many things.
It's not really a good news story because we were merely passengers on this out of control bus which happily stopped at an OK place. She has told us that it was a "phase" - her word - and that's over now. As for your worrying, we worried ourselves silly even though we knew it was pointless, but this is my child here and I'm not made of granite, of course I worry like hell about her. Overlay worry with a knowledge of your helplessness and you get the concept of how it feels as I'm sure you do. She chose to let herself recover, we were locked out of her world and couldn't help - an awful feeling for a parent - so we had little to do with her recovery.
All I can suggest is unconditional love and prayer if that's your thing. Try to keep your life going too, you're not much help to your child if you're an emotional wreck. That's what we did, more or less successfully - less rather than more I must admit. I truly wish you good luck with your daughter as she works herself out.
