I naturally have dry skin but I have an extra dry patch of skin under my left upper arm , slightly larger than the width of a pencil. It is circular and has 1 bump in the middle with the border of the dry patch being bumpy. It was very itchy the first day and is now only itchy when I touch it. I have had it for just over a week now. I m concerned becuase I first noticed it on my way back from Zions National Park and I did see a horsehair worm on one of the trails and I m worried that I have some kind of parasite. I put my feet in the river like a ton of other people did but that is all that touched the water. I also just boarded my dogs while we were on our trip but I haven t seen any signs of anything on them. Should I be concerned or am I overreacting like I do a lot of the time?