It's chapter 14 of Leviticus that discusses what to do if leprosy is cured. But as my Bible points out in a footnote, this old school rendering of the Hebrew word is probably wrongly specific. As such, the term is just translated "defiling skin disease" or in the NVI just "su enfermedad" or reference to the "persona infectada".
It was confusing to me at first because the chapter begins by this weird ritual of killing one bird and dipping the other in its blood and releasing it, but then goes on to describe a sacrifice to be made clean--including a pauper's exception, btw. But then I realized that there is a difference between healing of the physical illness and being retored to ritual cleanliness. It is probably not insignificant that the latter has a pauper's exception, but not the former. The same two steps is true for the home. After the mold is gone then you purify the house. Lev. 14:48-49.
Chapter 14 also has a bit of awkwardness revealing its non-contemporaneous authorship, "When you enter the land of Canaan, which I am giving you as your possession, and I put a spreading mold in a house in the land ..." Lev. 14:33. This reads like a bad sitcom where the Pilgrims land on Plymoth Rock and say, "Thankfully this land will remain always pure and never be ruled by a woman or reality tv star."
Then, finally, with Leviticus 15 we get to the good stuff. What to do when (1) a man has an unusual bodily emission, (2) a man has an emission of semen, and (3) a woman has her regular flow of blood. **Spoiler Alert** all of these make one unclean.
Most interesting is that having sex also makes you unclean, although the restoration is no big.
16 “‘When a man has an emission of semen, he must bathe his whole body with water, and he will be unclean till evening. 17 Any clothing or leather that has semen on it must be washed with water, and it will be unclean till evening. 18 When a man has sexual relations with a woman and there is an emission of semen, both of them must bathe with water, and they will be unclean till evening.Lev. 15. huh.
[UPDATE 3/7: I discuss these chapters a bit with my pastor in this podcast.]