If the prey was only out a short time, if it's fully furred and if it was in top condition in the first place, then you're fine to re-freeze it. Do mark the freezer bag though as a re-freeze and use it up first for the next feed. If when you reheat it though it smells even the least bit funky, toss it (do this with any f/t prey refrozen or not). Usually pinkies don't do well with a refreeze as it tends to weaken their belly skin and cause exploding pinkies.

If there's any concern with a frozen prey though, as far as it's quality or "freshness" - best to toss it and not chance a problem for your snake.