I have sunburn on the top of my calves, right below the inside of the knee (?) and it stung like nothing other when I got into the bath and I honestly thought I had cut myself or had bites or something since I've only worn shorts about 10 times in the last five years and it's the first time my legs have been burnt.
The rest of my legs would have been burnt at the back if it wasn't for the size of my calves.