Leviticus 13:27-31

and the priest shall look at him on the seventh day. If it spreads farther in the skin, then the priest shall pronounce him unclean; it is an infection of leprosy.

But if the bright spot remains in its place and has not spread in the skin, but is dim, it is the swelling from the burn; and the priest shall pronounce him clean, for it is only the scar of the burn.

“Now if a man or woman has an infection on the head or on the beard,

then the priest shall look at the infection, and if it appears to be deeper than the skin and there is thin yellowish hair in it, then the priest shall pronounce him unclean; it is a scale, it is leprosy of the head or of the beard.

But if the priest looks at the infection of the scale, and indeed, it appears to be no deeper than the skin and there is no black hair in it, then the priest shall isolate the person with the scaly infection for seven days.