Smashed finger nail in iron door. Black nail right away. Finger sensitive painful and others fingers feel weird but they weren't smashed.

Finger pain. You probably have a subungual hematoma where there is blood under the nail which appears black. If you don't have a fine hole drilled through the nail quickly it will lift the nail off of the nail plate and you will lose the entire nail. If you feel uncomfortable doing it, go to the ER.The other fingers were probably just bruised. Good luck!