"Normal" Tzaraat becomes impure when spots keep spreading - Leviticus 13:1-8

If entire body becomes covered with Tzaraat, the person becomes pure - Leviticus 13:12-17

Completely-White Tzaraat is a different type of Tzaraat - Likutei Sichot Pt. 32 p.82-83

Pharaoh's Tzaraat - Exodus 2:23, Midrash Rabba 1:34