Hello Thank You for contacting HCM. Insect bite causes allergy resulting in swelling of that particular area followed by formation of rash of itch.You need not to worry. It will subside itself in few days. In the meanwhile i would suggest you following things: take cetirizine one at night for 5 days. Take a cloth and warm over flame, then place over the swelled area. It will give soothing effect. take acetaminophen for pain(if occurs) Report to hospital if: Condition remain same after 2-3 days Any unusual symptom appears Condition deteriorates. There is difficulty in breathing. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. Wishing you good health.