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.
Jewish Publication Society of America Version (JPS1917) - Leviticus 13:55 >And the priest shall look, after that the plague is washed; and, behold, if the plague have not changed its colour, and the plague be not spread, it is unclean; thou shalt burn it in the fire; it is a fret, whether the bareness be within or without.