Leviticus 13:4-5, 23

If the bright spot be white in the skin of his flesh, and in sight be not deeper than the skin, and the hair thereof be not turned white; then the priest shall shut up him that hath the plague seven days: and the priest shall look on him the seventh day: and, behold, if the plague in his sight be at a stay, and the plague spread not in the skin; then the priest shall shut him up seven days more

But if the bright spot stay in his place, and spread not, it is a burning boil; and the priest shall pronounce him clean.