1)
What is the word "Tahor Hu" coming to prelude?
1.
Sifra: It precludes a Metzora who comes to the Kohen covered with Tzara'as, whom the Kohen declares Tamei. 1
1
As is evident from the episode with Miri'am, which does not specify the location of the Tzara'as with which she was smitten. See Oznayim la'Torah, on Pasuk 12, DH 've'Im Paro'ach Tifrach'.
