By making a paste of baking soda and water you will relieve the pain and swelling. A topical hydrocortisone cream will help itching as well as taking oral benadril. If these remedies don't work, then I suggest consulting your doctor.
If the bite is red and itching, try dabbing on a paste of baking soda and water to relieve the itch. If the bite does not resolve in a day or two, if it becomes hot, swollen or infected, see a physician.