Leviticus 13:31-34

And after looking at the diseased place, if it does not seem to go deeper than the skin, and there is no black hair in it, then the priest will have him shut up for seven days: And on the seventh day the priest will see the place: and if it is not increased, and there is no yellow hair in it, and it does not seem to go deeper than the skin, Then his hair is to be cut off, but not on the diseased place, and he is to be shut up for seven days more: And on the seventh day the priest will see the place: and if it is not increased, and does not seem to go deeper than the skin, the priest will say that he is clean: and after his clothing has been washed he will be clean.