Leviticus 13:34-37

34 On the seventh day the priest is to examine the itch, and if it has not spread in the skin and appears to be no more than skin deep, the priest shall pronounce him clean. He must wash his clothes, and he will be clean.

35 But if the itch does spread in the skin after he is pronounced clean,

36 the priest is to examine him, and if the itch has spread in the skin, the priest does not need to look for yellow hair; the person is unclean.

37 If, however, in his judgment it is unchanged and black hair has grown in it, the itch is healed. He is clean, and the priest shall pronounce him clean.