I am not good at rash stuff really, but what we use is plantain. We have it growing in our yard so we pick the leaves, chew them slightly, and stick it on the area. Usually takes away most of the itchiness and promotes healing.
Witch hazel. tea tree, we use several different things (if you do not have plantain)
Do you have WAHM soap? Try rubbing that on and leaving it on. Dont wet it jsut rub it on dry.
Oatmeal in a washcloth or cloth bag may soothe if it itches.
Since you are wearing sandals, maybe you walked through something that your skin is sensitive to. (like poison ivy) or got chigger bites or soemthing.
Whatever it is, I hope you figure out how to help it
