Great tat Suntiger
Dont know what possessed you to get it there though Ouch!!! Like Matt was asking it would depend on alot of things but I would be carefull only because of where the tat is and there is alot of bacteria on a foot. You will want to keep it dry and in fresh air, just a thought!
When i got mine on my back though mind you, I did not swell at all so I cant help you to much with that part maybe if you did post a pic the ppl can give you a better idea weather it is normal or not.