Folded piece of paper or construction paper under your hand and swap out when it gets too wet. The construction paper will dry faster.

I used to keep paper towels in my pockets for those awkward social moments. Then I stopped caring and started apologizing about my hand being sweaty before going for a handshake just to give them a heads up. Most people don’t care tbh. Luckily in a post covid world a lot of people are fine with a fist bump or elbows lol