First of all an aspect that is created by a maneuver needs to be sticky if it is to be tagged/invoked in a sub sequential exchange. That means the maneuver has to generate at least one extra shift.
If it not gets sticky, then it can only be tagged once in the next exchange, because after that the aspect is gone. You might say the bad guy can get up again no problem ...
If it gets sticky, then it can be tagged once for free (only in the following exchange) or invoked via the use of a fate point. The bad guy has to struggle to get onto his feet again.
In your example your bad guy is unlikely to remain "Prone", as that's an undesirable place to be. He likely will try to get on his feet again. To do that he has to execute a maneuver of his own to get rid of the "Prone" aspect. If the good guy or one of his allies is in a position to prevent the bad guy from getting up, he may defend against the maneuver. In other words: The bad guy stays "Prone" until he has successfully gotten up again, probably against the will of whoever has made his face hit ground.
