According to WebMD, the easiest way to get rid of heat bumps is by allowing the rash to simply go away on its own. However, taking a cool shower, as well as keeping the affected area cool and dry, can also help get rid of heat bumps.
Another way to help eliminate heat rash is by letting the skin air dry after bathing or showering. Avoiding the use of oil-based skin products can also help reduce bumps caused by overheating. Heat rash is typically avoided by wearing loose fitting clothing, not exercising in excessive heat and keeping the body thoroughly hydrated during warm weather.