Bear in mind that his injuries heal much more quickly when he changes from one form to another, but it takes too much strength to change from one to another several times in succession; once is probably all he can manage. I don't think an amputated limb would grow back, but am willing to be convinced otherwise.
Male werewolf gets wounded while in
These are the best place/s for him to be injured:
The werewolf should be injured by: