The Illumination, by Kevin Brockmeier
In the opening pages of The Illumination, a woman cuts her finger with a knife and the wound emits a silvery light. At the hospital, she learns that this is happening all over the world—every site of injury, pain or sickness shines. A headache looks like a glowing orb, arthritic bones look like icy branches, a kidney stone is a ball of light barely visible underneath a shirt, open wounds are blinding.
The media call this event, when all the world's pain becomes permanently visible, the Illumination. At first a phenomenon, then cause for a media frenzy and hailed by some as a sign of the apocalypse, the glow quickly becomes the new normal. One might assume that the world would become more empathetic as a result of it, but if anything the characters in this novel become more insular.
Brockmeier is known for including supernatural elements in his fiction (his previous books, The Brief History of the Dead and The View from the Seventh Layer, have introduced ghosts, aliens and dystopian futures) without making them the focus of the work. The Illumination exposes the immense vulnerability of people living in a world "whose rules had suddenly changed."