How do you get rid of a normal skin rash?
Calamine as another person mentioned. But also add, keeping that area clean and dry. If it is an area that gets wet from sweat or you live in an area with high humidity...keeping it clean and dry will help it go away faster.
It depends on the cause. If it is from dry skin, aloe, or cocoa butter. If it is an infection, use Neosporin. Allergies, uses Benadryl.