This speaks of Gehazi and his descendant getting leprosy as if Naaman's leprosy was taken from him and given to Gehazi. Alternate translation: "you and your descendants will have leprosy, just as Naaman had leprosy"
The phrase "his presence" refers to the area where Elisha could see him. This means that he left the room where Elisha was. Alternate translation: "When Gehazi left the room, he was" (See: [[rc://en/ta/man/translate/figs-idiom]])
Leprosy makes skin white. Here Gehazi's leprous skin is compared to the color of snow. Alternate translation: "with skin that was white like snow" (See: [[rc://en/ta/man/translate/figs-simile]])