TT #92 · Parshas Tazria · Aliyah 1 · Passuk 4
English: But if it is a white discoloration on the skin of the body that does not appear to be deeper than the skin and the hair in it has not turned white, the priest shall isolate the affected person for seven days.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:4
Torah Temimah cites Sifra (Toras Kohanim) for the initial seven-day confinement period.
Sifra — Vayikra 13, Midrash Sefer
English: “The priest shall confine the affection seven days” — seven days initially.
Textual clarification
The first confinement period is seven days; this wording establishes the initial interval before the next examination.