Vayikra 13:18

שחין A BOIL — The word expresses the idea of heat. It is so called because the flesh has become inflamed by an injury which came about as the result of a blow and not as the result of fire (the latter case being mentioned in v. 24 and being termed a מכוה) (Chullin 8a). ונרפא AND IT BECAME HEALED — the boil (not the flesh also mentioned in this verse) became healed and in its place it produced another plague (the שאת mentioned in the next verse).

The flesh also, the skin of which has on it a pox which is healed,

וּבָשָׂ֕ר כִּֽי־יִהְיֶ֥ה בֽוֹ־בְעֹר֖וֹ שְׁחִ֑ין וְנִרְפָּֽא׃