Reapply liberally every couple of hours, more often if you sweat heavily. Many professional guides reapply sunscreen within a half hour of the first application, before they start to sweat, believing a double layer, allowed to dry, is more effective than single applications. People who are allergic to PABA, an ingredient in most sunblock, can buy PABA-free lotions. Thin gloves and face masks, sold in flyfishing shops, are another option that won't land you a modeling job in GQ, but will save your skin from burning. Cool, wet compresses offer a temporary respite from sunburn pain.
Anesthetic sprays do, too.
The only difference with the latter is you have to pay for the relief, and it doesn't last much longer. Mentholated aloe vera lotions work better, as do anti-inflammatories such as Motrin or Advil. Heat exhaustion is the most common form of heat illness. It is caused by the depletion of the body's salt or water through exertion. Symptoms include nausea, headache, weakness, confusion, chills, faintness, and rapid pulse.