First, know what an allergic reaction to a sting is. An allergic reaction involves the whole body. There can be hives, shortness of breath, fainting, coughing, wheezing, or confusion. If these occur after a sting, call 911 right away.
Localized swelling around the sting with redness and pain is NOT an allergic reaction. Treat this with cold compresses and pain relievers. You can also rub some meat tenderizer on the are to help with the pain.