Leviticus 13:29-33

29“If a man or woman has a sore on the head or the beard,

30then the priest shall examine the sore; and indeed if it appears deeper than the skin, and there is in it thin yellow hair, then the priest shall pronounce him unclean. It is a scaly leprosy of the head or beard.

31But if the priest examines the scaly sore, and indeed it does not appear deeper than the skin, and there is no black hair in it, then the priest shall isolate the one who has the scale seven days.

32And on the seventh day the priest shall examine the sore; and indeed if the scale has not spread, and there is no yellow hair in it, and the scale does not appear deeper than the skin,

33he shall shave himself, but the scale he shall not shave. And the priest shall isolate the one who has the scale another seven days.