That was the true tragedy about Judas. Had he stuck around to see Jesus Resurrected, I have no doubt Jesus would have sought Judas out and if Judas showed remorse and horror at himself, Christ would have forgiven him. He might have then become the greatest Preacher next to Paul. Alas even the prophecies were against Judas, right down to the 30 pieces of silver.
Also consider Aaron, Moses older brother. He was chosen as High Priest to the Israelite nation, yet he forged a golden calf for the people to worship. What was his punishment and why did God not remove him from office over this blasphemous act?