Sputnik....how do you have any idea what, in fact, the vet did give the snake?

Chances are the vet administered a solution containing electrolytes, among other things, to give the snake's system a jumpstart. This is not a "meal replacement" and its effects could wear off in the timespan that you suggest waiting.

My advice, to you Vianky, is to leave a live fuzzy/hopper mouse with the snake overnight and see what happens. Fuzzy mice are not equipped to do any damage to the snake and a long period of calm and darkness may entice an otherwise weakened or reluctant feeder to at least get hungry and eat on its own. Give it a shot, and hope for the best!