For a normal sting: remove the stinger if there is one (bees leave them, wasps do not), wash the area, cold compress, and take an antihistamine for itch plus ibuprofen for pain. The thing that matters most is recognizing the allergic reaction signs, because those mean 911.
First steps: get the stinger out fast if present - scrape it sideways with a card or fingernail (pinching squeezes more venom in); only honeybees leave stingers, so if it was a wasp or hornet there is nothing to remove, and wasps can sting again, so move away calmly. Wash with soap and water, then a cold compress 10 minutes on, 10 off. The swelling, redness and pain of a normal sting peak over 24 to 48 hours - antihistamine (cetirizine or diphenhydramine) for itch and swelling, ibuprofen or acetaminophen for pain; a baking soda paste or hydrocortisone cream on the spot helps some people. Large local reactions - dramatic swelling spreading well beyond the sting (a whole hand or half a face) - look alarming, are not dangerous by themselves, and settle over days with the same care. The emergency is anaphylaxis, and it starts within minutes to an hour: hives spreading beyond the sting area, swelling of lips, tongue or throat, hoarseness, trouble breathing or swallowing, dizziness or faintness, vomiting - use an epinephrine auto-injector if one exists and call 911; even after epinephrine works, you need the ER because the reaction can rebound. Stings inside the mouth or throat, or many stings at once (dozens), are emergencies by themselves. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.
What to do
Common questions
What's the difference between a normal reaction and an allergic one?
Normal: pain, redness and swelling confined to the sting area (even a few inches around it), peaking over a day or two. Large local: dramatic swelling spreading well beyond the sting - a whole arm or half a face - uncomfortable and impressive but not dangerous, settling over 3 to 10 days. Allergic (anaphylaxis): symptoms AWAY from the sting - hives across the body, swelling of lips/tongue/throat, hoarse voice, wheezing, dizziness, vomiting - starting fast, usually within minutes to an hour. That third category is the 911 call.
Do wasps leave stingers, and can they sting twice?
Only honeybees leave a stinger (it tears out with part of their abdomen, killing the bee). Wasps, hornets and yellow jackets keep theirs and can sting repeatedly - which is why the first move after a wasp sting is walking away calmly rather than swatting: a threatened wasp releases alarm pheromones that invite its nestmates. If you disturbed a nest, distance first, first aid second.
How long does a wasp sting take to stop hurting and swelling?
The sharp pain fades within hours; the swelling and itch build over 24 to 48 hours (the day-2 peak surprises people into thinking it is infected - it usually is not) and resolve over 3 to 7 days. Large local reactions can take up to 10 days. Actual infection is uncommon but shows differently: increasing pain and redness after day 3, warmth, pus, or fever - that pattern earns a visit.
I was stung near my eye / inside my mouth - is that different?
Yes - location upgrades the stakes. Stings in or around the mouth, tongue or throat can swell into the airway: seek emergency care promptly even without allergy signs, and suck on ice while heading in. Eye-area stings deserve same-day medical assessment - the eye structures are too delicate for watchful waiting. And multiple stings at once (a dozen or more) warrant medical evaluation regardless of allergy, because venom dose matters. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.