I can't speak from experience in Jamaica, but we go camping in the FL Keys every year, and the no-see-ums and mosquitoes love me. The no-see-ums tend to bite like crazy from the knees down, and then nothing... until a couple of days later when the welts appear on me. Sometimes I'll have new welts appear days after getting home. I don't think I've ever had a 6 day delay though- that's a new one on me. Benadryl cream for the itch?