My son came back from a day at Typhoon Lagoon with a bumpy, raised, itch rash all over his back, belly, shoulders, neck, and arms. It was tiny bumps everywhere, a little raised, fairly red, and very itchy. It calmed somewhat the next day (at least wasn't as red or itchy - and I was applying hydro-cortisone cream), but the bumps stayed for several days. I don't think it was anything light related or sunscreen related because I had him in a sun-blocking swim t-shirt (and life jacket) and most of the bumps - but not all - were in areas that were protected from the sun physically. He's in water and sun all the time and we'd never had that issue before. He also got a pretty severe outer ear infection (swimmer's ear) from that trip - which he's never had before. I really think it had to something specifically with the water in those pools or one of those pools, but I'm not sure and there's not really any way to know. I wonder if it could have just been a reaction to the chemicals or bacteria in the water for yours, too?