Leviticus 13:18-23

18“When the body has a boil on its skin and it has healed,

19but in the place of the boil there is a white swelling or a bright reddish-white spot, then it shall be shown to the kohen.

20The kohen is to examine it, and behold, if its appearance is lower than the skin and its hair has turned white, then the kohen is to pronounce him unclean. It is a plague of tza'arat that has broken out within the boil.

21But if the kohen examines it and sees there are no white hairs within, and if it is not deeper than the skin but is faded, then the kohen is to isolate him seven days.

22If it spreads in the skin, then the kohen is to pronounce him unclean. It is a plague.

23But if the bright spot stays in its place and has not spread, it is merely the scar from the boil—the kohen is to pronounce him clean.