en_tn/lev/13/09.md

he must be brought to the priest

AT: "someone must bring him to the priest" (ULB) or "he must go to the priest" (See: rc://en/ta/man/translate/figs-activepassive)

if there is raw flesh in the swelling

Here "raw flesh" could refer to open sores on the skin. Or it could refer to new skin that has grown but the area around it is still diseased. Either way it indicates that the skin disease is not healing properly.

chronic skin disease

This is a disease that continues or reoccurs for a long time.