I also compulsively scratch my head and scratch my nails. As well as strong impulse to SI in times of high emotion. Whats been helping the last few months is hand cream. Every time I want to do something destructive with my hands I put on hand cream. I have a lavender scented one which is quite soothing and a few others around too. I also got this massage bar from Lush and rub that between my hands. Sometimes I use a little on my shoulders too. I think self-massage reduces cortisol so...