Many years ago, I caught my index finger in a door , it got black and the nail fell off a few months later. Any way, I had a dental appt a week after I had caught the finger. He told me if it had happened just the day before my appt., he would have drilled a hole in the nail to release the pressure so it doesn't throb so much. You might go to an emergency room. I know they have ways to accomplish the same thing.