I have a swollen, pimply rash under my armpits and behind my knees. It started under just one arm and within two days had spread to the rest. Any ballpark ideas of what it is and how maight I treat it. Currently I am taking bendryl orally and topically using a couple of different options. One was a anti- itch lotion that helped with the itch but made the area swampy and the other was a powder but it only worked for short time.