What are the implications of the (otherwise superfluous) words "ve'Im Tachtehah Ta'amod ha'Baheres"?
It is not clear as to why the Sifra learns the same thing from two different sources.
What is the definition of "Tzareves ha'Shechin"?
Sifra: It is a crust the thickness of a garlic-peel, 1 even though the mark of the boil is still visible.
See Torah Temimah, note 92.
Why is a Nega on the location of a boil or a burn Tahor after one week, and not two weeks like a Nega on the skin?
Oznayim la'Torah: Because, whereas regulat skin is tough an it can take up to two weeks for the Si'man Tum'ah to break through, the crust that grows on the location of the boil or the burn is thin, and if the Si'man Tum'ah has not appeared after one week, it obviously isn't there and won't appear any more.
