Why does the Torah insert the word "me'Cheiko" here, but omit it in the previous Pasuk?
Rashi: To teach us that Hashem's Midah of goodness works faster than His Midah of punishment. 1
Because "me'Cheiko" implies that even whilst his hand was still in his bosom the skin had reverted back to normal, whereas when it only turned into leprosy after he had removed his hand from his bosom (Rashi).
Why does the Torah not mention Kaparah and Selichah by the Chatas of the Kohen Gadol, like it does by those of the Tzibur, the Nasi and the commoner?
Ramban (2), Moshav Zekenim (2) #1: Due to his distinguished status, he does not attain full atonement with his Korban, until he prays and implores Hashem to forgive him. 1
Ba'al ha'Turim, Moshav Zekenim (2) #2: Due to the Mishnah in Pirkei Avos (4:16) 'Shigegas Talmud Olah Zadon' (he is considered Mezid). 2
Moshav Zekenim: Also the Kohen Gadol's Chatas is when the nation sinned due to him. The coming Parshah (a mistake Hora'ah of Beis Din) is connected to this Parshah. What it says there (verse 20 - "v'Chiper
Why does the Torah not say about Haktaras Emurim of Parim ha'Nisrafim "Re'ach Nicho'ach" or "Isheh la'Shem"?
Ramban (2), Moshav Zekenim (2): This is because part of the Korban (the bulk of the animal) was burned outside the Mishkan. It is not Isheh la'Shem.