Leviticus 13:18 (KJV)

Then the priest shall consider: and, behold, if the leprosy have covered all his flesh, he shall pronounce him clean that hath the plague: it is all turned white: he is clean.

But when raw flesh appeareth in him, he shall be unclean.

And the priest shall see the raw flesh, and pronounce him to be unclean: for the raw flesh is unclean: it is a leprosy.

Or if the raw flesh turn again, and be changed unto white, he shall come unto the priest;

And the priest shall see him: and, behold, if the plague be turned into white; then the priest shall pronounce him clean that hath the plague: he is clean.

And in the place of the boil there be a white rising, or a bright spot, white, and somewhat reddish, and it be shewed to the priest;

And if, when the priest seeth it, behold, it be in sight lower than the skin, and the hair thereof be turned white; the priest shall pronounce him unclean: it is a plague of leprosy broken out of the boil.

But if the priest look on it, and, behold, there be no white hairs therein, and if it be not lower than the skin, but be somewhat dark; then the priest shall shut him up seven days:

And if it spread much abroad in the skin, then the priest shall pronounce him unclean: it is a plague.

But if the bright spot stay in his place, and spread not, it is a burning boil; and the priest shall pronounce him clean.