Crying Time Again
When you've been crying, it's written all over your face. Your eyes get swollen and puffy.
Tears from crying are the very same ones that keep our eyes moist and comfortable, and wash out bits of dust and debris.
Those basic tear secretions are produced in the conjunctiva, the membrane that coats the entire surface of the eye.
Swell of Emotion
These basic secretions, though, don't overflow like the tears associated with emotional crying. Those tears are produced by the lachrymal gland, located in the upper, outer corner of our eyelids, and not only are they much more watery than basic tear secretions, but there are usually so many of them that they overflow and spill down your cheeks and drain through tiny ducts into your nose.
Emotional tears are more watery and less salty than basic tear secretions and the tissue in your eye. So, through the process of osmosis, the water moves into the saltier ocular tissues, which makes them swell up. And then there's all that furtive eye rubbing to hide his tears, which inflames eyes even further. Still, even though it looks bad, the puffiness and irritation will eventually go away.
There's no known cure for puffy, swollen eyes but Kleenex has been known to help the situation.
"Crying Your Eyes Out" (New York Times)
"Why Do We Get Swollen Eyes After Sleeping or Crying?" (MadSci Network)