Hi,
The familiar symptoms of bee and wasp stings include pain, redness, swelling, and itchiness in the area of the sting. Multiple stings can have much more severe consequences, such as anaphylaxis, a life-threatening allergic reaction that occurs in hypersensitive persons.
Emergency medical kits containing self-administrable epinephrine to counter anaphylactic shock are available for allergic people and should be carried by them at all times. People who suspect they are allergic should consult an allergist about shots that can reduce reactions to bee and wasp venom.
Most stings can be treated at home. A stinger that is stuck in the skin can be scraped off with a blade, fingernail, credit card, or piece of paper (using tweezers may push more venom out of the venom sac and into the wound). The area should be cleaned and covered with an ice pack. Aspirin and other pain medications, oral antihistamines, and calamine lotion are good for treating minor symptoms.
ref:http://www.myonlinewellness.com/topic/topic100586519
After a few days if still swollen running hot water over the sting area makes it drain faster. Like hot water in the shower for 15 minutes twice a day on that spot. For me the swelling will stay for a good 2 weeks. But if I repeat hot water over the sting area I an make it go away in just a few days. By now you would have known if you were allergic. So if you had an allergic reaction other than swelling take antihistamine before running hot water over it.
The benedryl 2% cream works great too right after you clean it the day you are stung. But days later the hot water seems to help me the most. As hot as you can comfortable handle it. Not scolding just hot since you need to stay under it for 1--15 minutes. So not too hot.