The blister is the blight of pink skin, skin that is naïve and pathetically pretty in its newness.
But, upon closer examination, it is evident that the blister is a defense mechanism, built to protect guileless skin from repetitive friction and heat and heartache. It may hurt like hell by the end of the race, but that bloody blister will help your skin heal; it will be the cushioning your wounded derma needs to pick up the pieces.
This is how it happens: your feet caught in the embrace of your socks caught in the embrace of your sneakers run along on a high of endorphins and pheromones, a concoction of extravagant fantasy of feet that were meant to walk bare, not fly. The fragile layers of their skin separate and the emptiness that results isn't empty for very long: it swells to a tear-filled tautness until it bursts. But feet never do learn their lesson. They subject their skin to the same process of heat and friction and heartache until, eventually, the skin--too tired to hollow itself out, too tired of tears--becomes so hard and so calloused that it no longer needs blistering to survive. Under layers and layers of scar tissue, the skin is strong enough on its own and immune to bouts of long-distance fancies.
And runners keep on running.