The skin is just one simple barometer to adequate diet, drinking enough water, getting enough sleep, all the the things that encompass taking care of the "invisible" training.
Some, of many, options for athletes to consider might be to reduce carbs (grain sources)/sugars in the diet and make sure they are getting enough good fat (i.e. omega-3's, avocados, olives, oils, nuts) and vitamin D/sunlight exposure (which can be a real "catch 22" in the winter months with the negative cycle of a drop in vitamin D to subsequent drop in serotonin to increased carb craving to decrease fat metabolism and on and on; too many factors... just test things out to see what works best), just maintaining a good diet and obviously drinking enough water. Also using a humidifier in the bedroom for sleeping can really help, and not eating large meals, especially those with high amounts of carbs/sugars and sodium before bed is important (going to bed a slight bit hungry can go a long way). Use of healthy natural lotions; good hygiene is important, but excessive bathing and the use of soaps can compound the effect of being dehyrdated... maybe cleaning up one's diet so they don't sweat out s**t all the time would decrease the need to shower all the time because of some unique odor.
Like anything else however, good health measures will take care of the body (and mind; like there's a seperation); the skin is just a good and simple gauge to some potential possibilities of what's happening inside. Location, climate type of that location, and individual skin colors are other factors which can determine outcomes and should be considered. There's nothing novel here, but just something to look at, be aware of, and educate the athletes on as the winter training cranks up with the re-start of school.
"Maybe it's Maybelline"... maybe it's not.