Leviticus 13:4-5, 23

If the bright spot is white on the skin of his body and does not appear to be deeper than the skin, and the hair on it has not turned white, the priest shall isolate the person who has the infection for seven days. The priest shall examine it on the seventh day, and if in his estimation the infection has not changed and has not spread on the skin, then the priest shall isolate him for seven more days.

But if the bright spot remains where it is and does not spread, it is the scar of the boil, and the priest shall pronounce him clean.