His forehead — So that he could not hide his shame: though it is probable it was also in the rest of his body. From beside — By a stroke from an invisible hand coming from the altar; that he might be assured this was the effect of God's displeasure.
Related Commentaries of 2 Chronicles 26:19
2 Chronicles 26:19
19 Then Uzziah was wroth, and had a censer in his hand to burn incense: and while he was wroth with the priests, the leprosy even rose up in his forehead before the priests in the house of the LORD, from beside the incense altar.