TT #78 · Parshas Tazria · Aliyah 1 · Passuk 2
English: When a person has on the skin of the body a swelling, a rash, or a discoloration, and it develops into a scaly affection on the skin of the body, it shall be reported to Aaron the priest or to one of his sons, the priests.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:2
Torah Temimah cites Sifra (Toras Kohanim) for distinguishing which priests may examine skin afflictions.
Sifra — Vayikra 13, Midrash Sefer
English: “He shall be brought to Aaron the priest”—this might mean Aaron himself alone; how do we include another priest? The text says “the priest.” How do we include a priest with a physical defect? It says “of his sons.” Could this include disqualified priests? The text says “the priests,” excluding them.
Textual distinction
“Of his sons” includes a priest with a physical defect; “the priests” excludes priests disqualified from service.