As the central figure of The Crucible, John Proctor is faced with each of the play's conflicts. He is challenged to achieve moral integrity and humility and challenged also to tell a difficult and unpopular truth which may cause him to be harmed or killed.
Proctor's initial conflict is an external one. He tries to convince Abigail that all bonds between them are broken and that she should not expect anything more from him yet she refuses to accept this. She represents a failure of integrity for Proctor and dealing with her, as well as his wife, is Proctor's first external conflict.
He asks for forgiveness from Elizabeth, his wife, and attempts to humble himself before her, admitting his failure. When she won't absolve him at all, he is forced to choose between forgiving himself or continuing in his state of guilt. This is his internal conflict.
In the end, Proctor accepts his failures and recognizes that one failure does not forfeit his soul. He forgives himself and finds his moral integrity once again intact.
The external conflict Proctor initially faces is resolved in the resolution of his internal conflict.
Another external conflict which Proctor faces is the central conflict of the play, dealing with an unpopular truth in public. Proctor must decide whether or not to put himself at risk by challenging the prevailing belief in witchcraft. In doing this he is going against the church leaders (the judges) and going against much of his community.
Proctor overcomes his fear and acts upon his beliefs. He speaks against Abigail and the court.
...he is determined to tell the truth, even if it means criticizing and antagonizing the investigators.
In doing so he is condemned to death, but he regains his moral position as a man of integrity, individuality, and dedication to the truth.