The answer is easier than you think. Have you ever had a sunburn so bad that it causes blisters? (I have, as a teen falling asleep on the beach.) Those sunburns are called second degree sunburns. With that amount of exposure, the least that would happen is a 2° sunburn over most of your body (some parts don't suffer this), which would lead to hypovolemic shock. Without treatment (which includes fluid resuscitation), you would probably die within 24 hours. If, by chance you survived the first 24 hours, the blisters that break open (and they would) would get infected because your immune system would be compromised by the damaged capillaries of the skin (that's one cause of the blisters in the first place.) Your lifespan would be a few days if you didn't die within the first 24 hours.

This is the best case scenario.

_{This is why burn units exist. Second degree burns over a certain percentage of your body are lethal.}

The answer is easier than you think. Have you ever had a sunburn so bad that it causes blisters? (I have, as a teen falling asleep on the beach.) Those sunburns are called second degree sunburns. With that amount of exposure, the least that would happen is a 2° sunburn over most of your body (some parts don't suffer this), which would lead to hypovolemic shock. Without treatment (which includes fluid resuscitation), you would probably die within 24 hours. If, by chance you survived the first 24 hours, the blisters that break open (and they would) would get infected because your immune system would be compromised by the damaged capillaries of the skin (that's one cause of the blisters in the first place.) Your lifespan would be a few days if you didn't die within the first 24 hours.

This is the best case scenario.

_{This is why burn units exist. Second degree burns over a certain percentage of your body are lethal.}