Charles Ellicott Commentary Leviticus 14:17

"and of the rest of the oil that is in his hand shall the priest put upon the tip of the right ear of him that is to be cleansed, and upon the thumb of his right hand, and upon the great toe of his right foot, upon the blood of the trespass-offering:" — Leviticus 14:17 (ASV)

And of the rest of the oil. —With the rest of the oil both priests returned to the leper, when the officiating priest put it on those parts of the convalescent’s body on which he had previously put blood, so that the oil now actually was upon the blood of the trespass offering, on the tip of the ear, the thumb, and the toe of the cleansed leper. (See also Leviticus 14:28.)