I got bit by something a few months ago on the top of my foot. It swelled up and itched like crazy! After a few days the swelling and itchyness moved to the side of my foot and a few days later moved under my foot. I thought it was strange that it moved around but it eventually went away! Well out of no where the swelling and itchyness keeps coming back and stays for a few days also. Do you have any idea what it could be??