Erythema, bullae, and vesicles on the hands of a dental student.

A 24-year-old female dental student with no known medical history reported a 3to 4-day history of painful blisters on the dorsal surface of both hands (Figure). She reported that the blisters began 1 to 2 days after she was boating at a local lake. While on the boat, she reported that she was preparing mojitos, a traditional Cuban cocktail that contains freshly squeezed limes, rum, sugar, mint, and carbonated water. What is the diagnosis?