The nail will grow back, but it may have a groove or dent in it. If part of the fleshy part of the finger was lost, a hook nail may result. This occurs when the nail grows in a hook over the end of the finger or toe. If the nail was removed, or if there is a large nail bruise, then the injured nail will probably fall off as a new nail grows back. It will take 4-6 months for a new fingernail to grow back, and 12 months for a new toenail.
Infection can occur.
It is more common with bite injuries or contaminated wounds. It is also a risk for people with diabetes, AIDS, chemotherapy, poor circulation, or other problems that may decrease the ability to fight infection. Although most nail injuries are accidents, some precautions can be taken to reduce the chances of this happening. Keep nails trimmed short to keep them from snagging on objects. Always keep the supporting hand out of the potential path of a box cutter or other sharp object.