What were the consequences if the symptoms spread in the skin?
Leviticus 13:22 (ESV)
22And if it spreads in the skin, then the priest shall pronounce him unclean; it is a disease.
If the infection spread, the person would be declared unclean. The construction, “really spread” (known as an infinitive absolute) emphasizes that the growth was noticeable and extensive.
22 And if it spreads in the skin, then the priest shall pronounce him unclean; it is a disease.