TT #141 · Parshas Tazria · Aliyah 2 · Passuk 15
English: When the priest sees the raw flesh, he shall pronounce the person impure. The raw flesh is impure; it is tzaraas.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:15
Torah Temimah cites Sifra (Toras Kohanim) for the distinct case in which extremities reappear after the whole body had become white.
Sifra — Vayikra 13, Midrash Sefer
English: “He is impure” means he is impure; one whose whole body became white and whose extremities later returned is not made impure by that return.
Textual derivation
This is the case where the body first became entirely white and the extremities later reappeared; the Sifra treats that return differently from an initially all-white condition.