Totally unsubstantiated, but there was buzz earlier that he had his chest waxed so he’d take pretty pictures on that first go around shirtless, AND that his chest/body is white, leading to further speculation that he darkens up his face to look more black and appeal to his base. Hey, if vanity was his only sin I could endure the guy, unfortunately, not so.
See the pics from a few years back in post #8...
You can clearly see the skin that was covered by his shirt and his wristwatch...
His face and arms are dark from all the Golfing.
His face is clearly darker in that photo of him carrying the snorkel.