A sweat-friendly haircut can make a huge difference - a wash-and-go style that you can just run your fingers through at your destination and let it dry.

I sweat pretty heavily too, and it's amazing how much fresher I look and feel just toweling off and changing into dry clothes, even without a shower. I'm not sure I could get away with it at someplace super businesslike, but for less-formal offices and social situations, it's plenty.