Turn over the foreskin folds have red packets (red blisters), may be genital herpes, may also be caused by other diseases. 1. genital herpes: a sexually transmitted disease caused by herpes simplex virus infection, if there is sexual contact with the patient, turn over the folds of the foreskin with red blisters, may be the early manifestation of genital herpes, with the progression of the disease, the formation of localized blisters, ulcers and other symptoms. 2. other diseases: a variety of pathogenic infections caused by phimosis, contact dermatitis, urticaria, trauma, masturbation and other stimuli can also cause red blisters in the folds of the open foreskin. The red blisters in the folds of the foreskin, need to go to the hospital to check the cause of the disease, just based on a symptom can not be diagnosed.