I'd guess all the standard remedies for jelly fish stings would work - same issue - the enzyme injected by the ant (jelly fish) is what causes the irritation and needs to be broken down.
1) Ammonia - take household cleaning ammonia and wipe on the bites 2) Adolph's Meat Tenderizer - make a paste of this plus water and apply. The tenderizer contains agents that break down the enzymes.
Just checking - but you are sure it was fire ants and not chiggers? I'm asking b/c chiggers require a different treatment than what I said above.
Even more OT, I was at my father's ranch in the hill country and saw an armadillo on his property. Don't know that I have seen one in 20 years, which tells me that the fire ants have moved out, or found a natural enemy, or all that Amdro TAMU gave out is finally working. Best way to fix the stings is to avoid them.