We were in Cancun the week of July 22 of this year. My husband noticed that he had a red rash with some small water blisters in the middle of it right below his waist band of his swim trunks. We put hydrocortisone cream on it and he took some antibiotics. The blisters went away but the red rash is still there (a month later!) The rash is not as red as it was in the beginning but it is there - no itching, no pain - just red! He didn't feel anything bite him while in the sea, but he was sitting on rocks in the water for quite a while the day he noticed it. Does anyone know what this could be? I would appreciate any ideas!