That's good ! I never heard of that before. (Maybe because
I've never been stung by an ant.)
When an ant bites or stings, it injects a tiny amount of 'formic acid'
into your skin. Soon, the formic acid itches, burns, and stings, and
after a while, a little piece of skin dies and falls off. Some people
are seriously allergic to it, and it can make them really sick.
'Acids' and 'bases' are opposites, and one can neutralize (cancel out)
the other. Tony is putting a weak 'base' on the sting, to neutralize the
formic acid that the ant left him as a little gift.
