Fill the tub up with mildly luke warm/cool water. Take regular distilled (white) vinigar and pour in about a cup or 2 depending on how well you think you can handle the smell. ( I personally love the smell of vinigar

Sit in the bathtub for as long as you can, you know like until you get raisin fingers. This allows the skin to really become saturated and the pores to fill with the water and vinigar. When you get out do not towel dry or anything, just stand on the mat until you are dry.
Then get regular good old Noxema, the kind in the blue tub. Basically coat yourself with it, you should not rub it in until you can't see it. The goal is to leave a thin white layer and let your skin absorb the excess.
When all is said and done, take a few tylenols or motrin (every 4 hours). Try to not put on clothes. I am not saying this to be dirty but you really need to leave your self open to the air. Depending on how bad it is you should do these steps about 2-3 times the first day. It should start to feel better by the 3rd day at least.
I grew up on the beach in California, I was a walking sun burn for 90% of my childhood.