A character who's taken more penalties than his or her Stamina may (as a 'free' action) make a Will roll (with no penalties) against the number of dice the character is trying to be able to use next round, up to his or her maximum score.

Note: When using Will to override damage penalties, success means you get the full amount you were rolling against, not just the number of victories scored on the Will roll, so if a roll of Will 3 vs Stamina 5 scores 1 victory, the character still gets to use the full 5 Stamina for the action. [1]

Damage penalties always apply to the character's next roll, whether in the current round or in the next round. Don't "time" the penalties; just say, "next roll".