Saw this happen in a state semi-final match years ago. Kid is behind 7 points with 30 secs left in the match and gets returned to the mat hard. . Heads to the middle of the mat ready to go when his coach starts yelling for him to stay down.

If you are injured bad enough to not finish a match I'm not sure what the injury would be that would heal so quickly to allow you to wrestle later that day or tourney.