Hi ! Most likely you have developed a hematoma
(collection of blood) under your nail.This usually though painful is a self limiting condition. If it increases your discomfort more, then you may visit your family physician, who may advise some anti inflammatory drugs for you and also an antibiotic if need be on physical inspection of the wound. He may also advise you for a shot of tetanus toxoid injection
, if you did not have one earlier.
Wishing you an early recovery.