TT #210 · Parshas Tazria · Aliyah 5 · Passuk 36
English: the priest shall examine him. If the netek has spread, the priest need not seek yellow hair; he is unclean.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:36
Torah Temimah cites Sifra (Toras Kohanim) for yellow hair returning after a person was released.
Sifra — Vayikra 13, Midrash Sefer
English: “He is impure”—the Sifra asks how we know that yellow hair which returns after the person was declared exempt can again establish impurity. It derives this from “the priest shall not inspect the yellow hair; he is impure.”
Textual derivation
A previously released case can become impure again when the qualifying yellow hair returns.