22 If it is spreading in the skin, the priest shall pronounce them unclean; it is a defiling disease.

Read Leviticus 13:22 Using Other Translations

And if it spread much abroad in the skin, then the priest shall pronounce him unclean: it is a plague.
And if it spreads in the skin, then the priest shall pronounce him unclean; it is a disease.
If during that time the affected area spreads on the skin, the priest must pronounce the person ceremonially unclean, because it is a serious disease.