TT #161 · Parshas Tazria · Aliyah 3 · Passuk 22
English: If it spreads in the skin, the priest shall pronounce him unclean; it is an affliction.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:22
Torah Temimah cites Sifra (Toras Kohanim) for the additional rule introduced by the repeated wording about spreading.
Sifra — Vayikra 13, Midrash Sefer
English: The repeated wording 'if it spreads' signals an additional rule.
Textual derivation
The repetition signals that the spreading rule covers further cases beyond the first timing expressly stated in the verse.