Leviticus 13:20-22

New Century Version

²⁰ And the priest must look at it. If the spot seems deeper than the skin and the hair on it has become white, the priest must announce that the person is unclean. The spot is a harmful skin disease that has broken out from inside the boil. ²¹ But if the priest looks at the spot and there are no white hairs in it and the spot is not deeper than the skin and it has faded, the priest must separate the person from other people for seven days. ²² If the spot spreads on the skin, the priest must announce that the person is unclean; it is a disease that will spread.