We had to spray three nests which showed up in our front yard. I would also suggest witch hazel for the itching, but I also second the ice. The other thing which helps itching, at least from chicken pox, is a blow dryer set on cool. Worked with all three of my kids.
The other thing I would use immediately, but it's not too late even now, is iodine. Just use a cotton ball or q-tip and dab it on each sting. It will kill germs without suffocating the skin/healing process. I had a vet recommend it to me as a first aid for any critters injured, though cut with water. I never use an antibiotic as it does suffocate the healing process as someone said up thread.