Leviticus 13:20-23

²⁰and the priest hath seen, and lo, its appearance is lower than the skin, and its hair hath turned white, and the priest hath pronounced him unclean; it is a plague of leprosy — in an ulcer it hath broken out.

²¹'And if the priest see it, and lo, there is no white hair in it, and it is not lower than the skin, and is become weak, then hath the priest shut him up seven days;

²²and if it spread greatly in the skin, then hath the priest pronounced him unclean, it is a plague;

²³and if in its place the bright spot stay — it hath not spread — it is an inflammation of the ulcer; and the priest hath pronounced him clean.