After it has been washed, the priest is to reexamine it, and if the mildewed article has not changed in appearance, it is unclean. Even though the mildew has not spread, you must burn it, whether the rot is on the front or back.
This is the law concerning the plague of leprosy in a garment, whether linen or woollen. A leprosy in a garment, with discernible indications of it, the colour changed by it, the garment fretted, the nap worn off, and this in some one particular part of the garment, and increasing when it was shut up, and not to be got out by washing is a...
Commenting on Leviticus 13:47-59
And if it appear still in the garment, either in the warp, or in the woof, or in anything of skin,.... After the piece has been rent out, in another part of the garment, &c. where before it was not seen: it is a spreading plague; or leprosy; a flourishing one, as the word signifies, a growing and increasing one: thou shalt burn that wherein...
And the priest shall look on the plague, after that it is washed: and, behold, [if] the plague have not changed his colour, and the plague be not spread; it [is] unclean; thou shalt burn it in the fire; it [is] fret inward, [whether] it [be] bare within or without. (q) But remain as it did before. (r) Or, whether it be in any bare place before, or behind.