Hi, my mum has just returned home from Spain and she has a sore on her heel. I told her to go to doctor yesterday, which she did and he said it was a blister, but it is about 1.5inches round and is red and black and blue, I have never seen a blister like this, and he has also given her antibiotics ......should I be worried and is there anything else I can do....the only time I have ever seen any thing like this was when I saw a heel ulcer. I am worried that the flight may have made it worse or that she may have been bitten by something in Spain as she was also walking on the beach in saddles and barefoot... Thanks TANIA