We need to know more information. Did you get an x-ray of the leg, what was his temperature, CBC (complete blood count) if so, what were the results? There is a possibility that the band may have done some internal damage, i.e., constriction or just general abrasion which aggravated the surrounding tissue.

Is he able to swim? Place him in a container with water so that he cannot touch the bottom and watch to see if he has normal range of motion. This will let you know if it is a weight bearing issue. Any information that you could render would help us but at this time we really cannot ascertain exactly what might be occurring. The Regal Swan