###Human: After sex, had yellow clustered blisters on vagina. What could it be? ###Assistant: Hi. I have reviewed the attached photographs (attachment removed to protect patient identity). The closely grouped fluid filled blisters and yellow crusted lesions seem to be most likely herpes infection. You do not have to apply Acyclovir cream as it will not be much effective in genital herpes. You should start with oral antiviral like tablet Acyclovir 400 mg thrice daily for a week and apply topical antibiotic like Mupirocin cream on the lesions twice daily. Do not use soap over the affected areas and wash only with plain water. Caused by herpes virus; either HSV1 or HSV2 (herpes simplex virus 1 or 2). Herpes genitalis. Avoid intercourse till the healing of lesions.