ויקרא כא:כא הלכה: Sefer HaChinukh

That a priest with a transient blemish not serve: That a priest with a transient blemish not serve, as it is stated (Leviticus 21:21), "Any man that has a blemish from the seed of Aharon the priest shall not come forth" - [the] word, "any," is an inclusion; and it includes a transient blemish. As at the beginning, it warns about a permanent blemish, such that I would reason that it is permitted to serve with a transient blemish which is less weighty than it. Therefore it warned about the transient, and that is the garav and the yalefet.