Sounds like they got swarmed by sand fly. The sand flies start to swarm just around the time the sun is going down or when it rains. Just get off the beach before that time and you'll avoid the little pests. Everything bites me first. So I use a product called Repel. It's supposed to be all natural and not that expensive. You can get it in most any grocery store in Negril, on the beach or in the west end... Good luck!

Robin