Did he come back and destroy Mondale? I don't think he did. Remember that Reagan didn't really have to do much; he was so far ahead. Yes, the line about my opponent's "youth and inexperience" was cute, but not the stuff that determines the election winner. The big fear going into that second debate was that Reagan would fall on his face again, and if THAT happened Mondale might have been able to make a real race of it. However, Reagan did fine and his performance was reassuring enough that it shut the door on the only small bit of hope that Mondale had left.
I should also add that Bush totally DESTROYED Ferraro in the VP debate which really stopped any momentum coming from the first Presidential debate.