You can heal wounds by hurting yourself again

If you intentionally damage yourself, any old wounds, both external and internal will heal immediately, as if they never happened. You will still be fatigued, and it has to be you doing the damage, so if you can't raise your arm when bleeding out etc you cannot have someone else cut a finger off you to use this power. This does not heal the wound you just produced.

The damage has to be at least as severe as a:

Flesh wound(pierces skin, flesh visible), broken bone, torn muscle, or twisted limb(the kind that heals over days, not the kind that just goes away after an hour or so)