Charles Ellicott Commentary Leviticus 13:33

"then he shall be shaven, but the scall shall he not shave; and the priest shall shut up [him that hath] the scall seven days more:" — Leviticus 13:33 (ASV)

He shall be shaven. —The priest, to be certain and to be able to examine the patient more thoroughly, is to have his head and beard shaved. This operation was performed by professional barbers, who were always readily available.

But the scall shall he not shave. —The place, however, where the scall appeared was not to be shaved, so that the priest might be able to see the colour of the hair. The manner in which the shaving was performed during the Second Temple was as follows: The hair around the scall was all shaved off, except two hairs on each side, close to the affected spot, to enable the priest to see whether the spot is spreading or not.