Our skin acts as a heat exchanger in the event of overheating of the internal organs. The sweat you get when you exercise vigorously or when it's hot is the body's way of saying the core or inner part of the body is too hot and needs to cool. This is carried out by the evaporation process which has a cooling effect and skin being rich in blood vessels carries this cooled blood back inside the body cooling it. Skin can also be a good indicator of health in case of unresponsiveness. Pale or colorless skin may mean that that the body isn't getting enough oxygen with all the blood being drawn by the internal organs to the heart to provide all it could.
As we can see, skin serves us many purposes so we have to take care of our skin and treat it with utmost respect and love it in the process.