Well that happened to me recently.
(Who am I kidding, that happens to me constantly. But here's just one example...)
My legs have been really, really white lately. Like 'woah, I'd better put on my sunglasses' white. And since it's summer, and I'm wearing slightly shorter skirts and even bathers from time to time, I'd decided during this Christmas break to find a way to make them a little less white.
Spray tans were out, because I've seen that episode of Friends where Ross keeps turning around at the wrong time and ends up with 8 layers of tanning spray on the front and none on the back, and I know (deep down, in that 'voice you should really listen to' place) that such a thing would somehow happen to me:
So I decided to do things the old fashioned way.
I was in Perth for a few days, and since they're in the middle of a (terrible - I almost died!) heat wave, we spent a good part of the first day in the pool. Perfect! I put sunscreen on my face, because I didn't want it to burn, but I didn't really worry about my arms because I've got a bit of a tan there anyway from work, and I figured I'd just keep a close eye on them in case they started to burn. And then I spent most of the day floating around the pool with my sunscreen-free legs propped up on a floaty for maximum exposure.
Had a lovely time, didn't feel any burning.
Got out a few hours later, and almost instantly realized that my arms and shoulders and back were heating up. Then they turned bright red and caught on fire.
*sigh* That's when I started to vaguely remember that sunburn doesn't show up till later *double sigh* Luckily my face was fine (turns out sunscreen actually works) and had just gotten a light tan (obviously should have gone with that approach on my shoulders, arms and back).
So over then next 4 days I had a new best friend, Aloe Vera (which some kind person somewhere had turned into a gel and popped into a bottle for me. THANK YOU ALOE MAN!)
So here's the final result:
1) Lots of pain
2) Not able to go swimming again for the rest of the trip
3) 80,000 more freckles than I had before I went out in the sun (which is not actually an exaggeration)
4) And I've now moved to the nuclear holocaust section of the cycle, with huge slabs of skin peeling off my arms/shoulders.
5) My legs are still completely bright white. Completely! They saw more sun than any other part of my body, but here they remain, completely impervious to the affects of the sun. It's like they have some kind of weird super power!
At least we know if we one day find ourselves in one of those Armageddon movie plots where the only way to save the earth from the asteroid is to send someone closer to the sun than any human being can actually withstand, to set off an explosion that will change the asteroid's course and save the world....
...we can send my legs.