Leviticus 13:21 KJV

19And 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;

20And 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.

21But 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:

22And if it spread much abroad in the skin, then the priest shall pronounce him unclean: it is a plague.

23But if the bright spot stay in his place, and spread not, it is a burning boil; and the priest shall pronounce him clean.