Woody's right on the Aloe Vera. Regular DMSO can dehydrate the skin and the rash can drive you nuts unless you keep adding water and more water on your skin right after the DMSO.
By using DMSO with Aloe Vera, the Aloe Vera hydrates the skin so less water is used but you can always spray some right after just in case.
The rashes of my brother went away when he started taking the Aloe Vera one.