I have the same problem, I have tried showering straight after, drinking plenty of water, using antibacterial face wipes, taking supplements to aid digestive system such as Milk Thistle, HR Clear etc, herbal remedied, nothing works, and I don't have to do that much exercise to get it, any form of exercise which causes sweating... and I also never used to get this either, it started after I turned 26, I am now 30, so I've been having the same problem but quite for some time.