John Gill Commentary Leviticus 13:35

"But if the scall spread abroad in the skin after his cleansing," — Leviticus 13:35 (ASV)

But if the scall spread much in his skin after cleansing.
] After he has been declared clean by the priest; for it was possible that it might spread after this, though so much precaution had been used, and so much time taken to observe it: with this compare (2 Peter 1:9) (2:20) .