Leviticus 13:17-21

And the priest shall see him: and, behold, if the plague be turned into white; then the priest shall pronounce him clean that hath the plague: he is clean.

The flesh also, in which, even in the skin thereof, was a boil, and is healed,

And in the place of the boil there be a white rising, or a bright spot, white, and somewhat reddish, and it be shewed to the priest;

And if, when the priest seeth it, behold, it be in sight lower than the skin, and the hair thereof be turned white; the priest shall pronounce him unclean: it is a plague of leprosy broken out of the boil.

But if the priest look on it, and, behold, there be no white hairs therein, and if it be not lower than the skin, but be somewhat dark; then the priest shall shut him up seven days: