John Gill Commentary Leviticus 13:36

"then the priest shall look on him; and, behold, if the scall be spread in the skin, the priest shall not seek for the yellow hair; he is unclean." — Leviticus 13:36 (ASV)

Then the priest shall look on him Again, and which is no less than the fourth time; for notwithstanding his being pronounced clean, he was still subject to the inspection of the priest, if any alteration appeared: and, behold, if the scall be spread in the skin; which was a certain sign of a leprosy: the priest shall not seek for yellow hair; or be solicitous about that, whether there is any or not, for either one or the other of these signs were sufficient to determine the case: he [is] unclean; and so to be pronounced.