If you have been stung by a wasp, there are several steps you can take to alleviate the pain and swelling at home:

1. Wash the affected area with warm soap and water to remove any bacteria or venom the wasp might have carried. This will also help wash out some of the venom left behind by the wasp.

2. Apply a cold pack wrapped in a thin cloth to the sting site for 30 to 60 minutes, in intervals of 10 minutes on and off. This will help reduce the swelling and pain of the wasp sting.

3. Take an anti-inflammatory medicine like ibuprofen to reduce the swelling and lessen pain from the wasp sting.

4. Apply an antihistamine, corticosteroid, or calamine cream to the entire red and swollen area to relieve the itchiness and alleviate the pain of the wasp sting.

If you have been stung in the mouth, nose, or throat, or if you experience symptoms such as difficulty breathing, rapid heart rate, severe decrease in blood pressure, or collapse, seek medical attention immediately.