Possible meanings are 1) his body would swell because of the snake venom or 2) he would become very hot with fever.
# nothing was unusual with him
This can be stated in positive form. AT: "everything about him was as it should be" (See: [[rc://en/ta/man/translate/figs-doublenegatives]])
# they changed their minds
To think differently about a situation is spoken of as if a person is changing his mind. AT: "they thought again" (See: [[rc://en/ta/man/translate/figs-metaphor]])