Insect bites often cause minor swelling, redness, pain, and itching. These mild reactions are common and may last from a few hours to a few days. Home treatment is often all that is needed to relieve the symptoms. The discomfort of many insect bites can be soothed by an ice cube, a cold washcloth, calamine lotion, a paste of baking soda, or an over-the-counter hydrocortisone ointment. If the bite or sting causes a severe reaction, seek immediate medical help.