Do you think it was ever painful for Sauron to be a flaming eye?

He chose his image to represent all he had lost. To never forget the pain it had cost him to come to this point. It was his right to claim all he gazed upon for he was lord of fire, fey magic, and bringer of decay. Let the hosts of middle-earth find an answer to that claim.

His fire did not harm him anymore than the fire in the belly of a dragon. The magic touched him and gave him control rather than taking it.

He was Sauron. The Abhorred and The Foul.

He was the shape changer.

Fear him.