Leviticus 13:8

13:8 The priest must then examine it, and if the scab has spread on the skin, then the priest is to pronounce the person unclean. It is a disease.

Leviticus 13:7

13:7 If, however, the scab is spreading further on the skin after he has shown himself to the priest for his purification, then he must show himself to the priest a second time.