This is an excellent question, particularly because the play gives no indication whatsoever as to what might happen to Christopher Sly after he finishes watching the play that is being enacted before him for his benefit. It is certain that at some point the Lord will reveal his joke, however, and that Christopher Sly will probably be mortified by the way that he was taken in and how he believed that he was actually a lord.
However, we do need to identify the parallels between the Induction of this play and the plot of the main play. Both stories involve a dare and the attempt to change another character into something else. Whether it is Sly being changed into a lord of Kate being changed into a meek and submissive wife, the theme of transformation is key. However, if we recognise that the transformation of Sly is based on nothing except illusion, that should lead us to question how permanent the transformation of Kate has been by Petruchio and what will happen during the rest of their marriage.
The short answer is that we do not know anything about Sly's fate. Perhaps we could say that what has been done to him is actually rather cruel. He has been played with in effect by a rich lord for his own diversion. Whether he will be able to go back to his former life and accept it happily again after believing he is a lord is a very key question to ask.