ויקרא יג:כב פירוש: רש״י וחזקוני

נגע הִוא IT IS A PLAGUE — this rising or bright spot is a plague (שאת and בהרת are fem., hence the fem. adj. הִיא).

נגע הוא, “it is a plague.” The word הנא is read as having the vowel chirik. It is in the feminine mode as it describes either the word: בהרת or שאת, both of which are feminine nouns.