I don't train at gyms without on-site showers. I had skin issues for years while I waited until I got home home, even though it was a short drive. They immediately vanished when I started showering right after class.
Combat sports in general are fucking gross. We had to toss a guy out of the gym because he refused to believe it wasn't cool to train in the morning, hang his gi on his car for a couple hours, then wear it again to train in afternoon (while not showering himself). And never mind the standard, "I have ringworm but it's all good because I covered it in tape" dude. Competition is even worse, with 25% of people showing to the tournament sick from over-training, tracking literal shit from the bathrooms to the mats, etc.