As a result, there's often a visible mark left after the injury heals.

When the injury heals, the pain stops.

"When the injury heals and you continue having pain beyond the time of expected recovery, that's chronic pain."

The black or purple-black color is caused by blood under the nail and will go away as the injury heals.

As it stands now, Elway could still lose some arm strength once the injury heals, Ting said.

Avoid raising your arm above shoulder level until the injury heals.

But once an injury heals, he said, the pain stops.

Trauma victims can also experience abnormal pain after an injury heals, Dr. Bennett said.

Until Ewing's injury heals and his form returns, Dudley has shown he can be an effective replacement.

The black appearance will most often go away as the injury heals, but this may take weeks.