Leviticus 13:2-5

2“When a man has a swelling on the skin of his body or a scab or a bright spot, and it becomes the plague-mark of tza'arat in his flesh, then he shall be brought to Aaron the kohen, or to one of his sons, the kohanim.

3The kohen is to examine the plague of tza'arat on his skin, and if the hair in the plague has turned white, and the appearance of the plague is deeper than the body’s skin, it is the plague of tza'arat. Thus the kohen should examine him and pronounce him unclean.

4If the bright spot is white in the skin of his body, but its appearance is not deeper than the skin and its hair has not turned white, then the kohen is to isolate the infected person for seven days.

5The kohen should examine him on the seventh day, and behold, if he sees the plague has not spread in the skin, then the kohen is to isolate him for seven more days.