Most hematomas are caused by an injury or some type of trauma. Your bird has more than likely injured its wing. Can you tell if it has a fracture? If you can gently maneuver the wind back in place, you can use vet wrap to secure the wing next to its body. If the wing is allowed to flop around, it can cause more injury. I know with human hematomas, cold compresses are used on and off, then heat after 48 hrs. Maybe someone else who has dealt with this can give you more advice. Hope your quail starts feeling better.