Container I have had skull & cross bones on the label.
One of my uses is for chiggers that dig into my skin. Kills the little buggers.
Chiggers don’t bury into your skin, they suck juices out of you like all nasty insects. The chigger bite is the wound, they, like ticks, inject nasty chemicals that then irritate you.
Prevention is the only way to, well, prevent them.
I usi suppose one could apply borax before exposure, but it dissolves in water, so sweat would mitigate it.