Perfluorodecalin is a fluorocarbon, a molecule that contains nothing else but carbon and fluorine. It's usually mixed with other fluorocarbons and goes by the trade name Fiflow. Fiflows are interesting materials: they are very stable (inert), heavy liquids that are neither water nor oil soluble but they create a third phase in emulsions. They can carry gasses, notably Oxygen, Nitrogen and Carbon Dioxide into the formula.
The manufacturer claims that Fiflow blends can have all kinds of good effects on the skin: they can have wound healing, muscle relaxation, and dermal filling effect and they might also improve skin renewal and skin elasticity.