Thanks For Being There. I Am An American Living In

Thanks for being there.
I am an American living in Geneva, Switzerland. In September we went to Turkey on vacation. I was bitten by something. Back in Geneva, I consulted my Generalist. He gave me some medication and told me that the bites might return. They did. In two months, I had blisters over the same area and I continued with the same medication. Now two months later, I have the same kind of blisters in other areas. Why?
Many thanks.