Unknown painful jellyfish sting at Kamaole Beach III, Maui

Swimming at around 5pm July 2, 2015 at Kam III beach in Kihei, Maui. Extremely painful sting. Source of sting was not sighted. Light blue residue remained on some areas of skin upon leaving the water. Unsure what type of jellyfish/organism but wound appears characteristic of a jellyfish/man-o-war.