TT #173 · Parshas Tazria · Aliyah 4 · Passuk 24
English: If the flesh has a burn from fire in its skin, and the raw area of the burn becomes a bright reddish-white spot or white,
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:24
Torah Temimah cites Sifra (Toras Kohanim) for the intermediate healing stage required for a burn.
Sifra — Vayikra 13, Midrash Sefer
English: The burn is neither still raw and oozing nor completely scarred; it is in an intermediate healing stage.
Textual derivation
The burn must be neither actively raw nor fully scarred; the rule applies in the intermediate stage described by the Sifra.