Burning, Blisters Around Vaginal Area, Grey Watery Discharge, Light Headed. Is It Yeast Infection Or Herpes?

My daughter has had only 1 sex partner, her boyfriend of 17 months. He claims he has had 3 sex partners prior to her but has never been unfaithful to her. She was on a trip to the Caribbean with him and his family when she began noticing burning and discomfort in her vaginal area. The next day she noticed that she had many blisters around the vaginal area and on her inner, upper thighs. She also experienced a clear or grayish, watery discharge and discomfort from walking. She had a slight headache, was somewhat nauseous and felt slightly lightheaded but those symptoms have mostly went away. She began using a suppository to treat a yeast infection but after 2 days has not had any relief of her vaginal symptoms. She just got home tonight and will see a dr? Do you believe she has a yeast infection or herpes?