a drawing representing John Proctor at the beginning and end of Act 3??

At the beginning of Act III, Proctor continues to be prideful and concerned with his own reputation above all else. That doesn't mean that he isn't working toward proving that his wife and the others have been unjustly accused, because he is. What it means is that he is still unwilling to put his own good name on the line in order to prove these things.

By the end of Act III, Proctor is humbled. He puts away his pride and realizes that his good name is not the most important thing in the world....... but truth is. Unfortunately, his truth comes too late to make a difference.