So what is this stuff anyway? Colloidal silver is a liquid suspension of silver particles. Waaaay back in the day, it was used medicinally to kill bacteria until something called 'antibiotics' were developed and found to be more effective. Not only were they more effective, but they did not have this interesting side effect: argyria. Seems that those silver particles, once absorbed by the skin either internally or externally, have a tendency to turn blue/gray when exposed to sunlight. Kind of like the silver particles in photographic paper darkening when exposed to light. As Dr. Oz said, he's essentially tattooed himself!
And finally, the reveal:
That's his fiance on the right. She met him after this had happened and like most women of a certain age, she wasn't discouraged when she learned he was blue. I wonder if she was thinking he just needed some cheering up?