I quite often wear makeup at the gym as I go after work or in the middle of the day if I get a chance. It hasn’t affected my skin at all. I will wear my usual eye make up and mineral powder foundation on my face. I religiously take it all off when I shower after the gym or the first chance I get. A good cleanser and exfoliator is essential though to keep skin clean and clear otherwise pores can get blocked with make up, sweat and skin oils. It is good for your skin to get red, that means you are working hard and your blood and oxygen are circulating!! Also sweating is one of your body’s way of eliminating toxins so sweat away, don’t worry about the redness, that is normal.