Parashas Metzora · Passuk 14:37
Chabad.org — English translation + Rashi
Torah Temima points to Toras Kohanim.
English: “Sunken [streaks]” — what are sheka’aruros? [Streaks that] appear sunken in their appearance.
Definition of the appearance
Chazal define the characteristic look of the house-nega as depressions or sunken discolorations in the wall.