Exercise. I thought this the other day as I was punching my hand against the wall. The pain in my hand was a lot like the pain in my heart or in my side after running for a while. As such I've started "self-injuring" with exercise that 1. let's me punish myself for all the destructive reasons and 2. makes me more fit and tires my mind so that I can't think about what was bothering me and 3. lifts melancholy as hormones flood your body. It really helps! Don't think of exercise as a way to ignore your self destructive desires, use it as a self destructive action. Self Injury demands pain not needless pain. Just chanel that destructive chaos into something that will make you feel better. All the while you're hurting yourself. Its been really helpful for me.