TT #121 · Parshas Tazria · Aliyah 2 · Passuk 10
English: If the eruption spreads out in the skin, so that the eruption covers all the skin of the affected person from head to foot, as far as the priest can see,
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:12
Torah Temimah cites Sifra (Toras Kohanim) for repeated spreading over the whole body, even when the eruption recedes and spreads again.
Sifra — Vayikra 13, Midrash Sefer
English: The rule applies even when the eruption spreads over the whole body, recedes, and then spreads again.
Textual derivation
Repeated spreading still falls under the rule even if the eruption recedes between episodes before covering the body again.