I was doing a roofing job in early winter ~1978, about 5F out, hands were pretty numb from the cold, and pounded that thumb. Looked like a squished grape blown out on the side, waited about 3 seconds for the pain to arrive at my brain. Duct tape and paper towel. Kept working but couldn't do much hammering for a couple days. Ever have to drill a hole in your fingernail to relieve the pressure or lose the nail?