Genital herpes and herpes Zoster are caused by two different viruses and cause two different syndromes. I recommend speaking with your primary care physician
in order to be evaluated. Genital herpes is caused by the herpes simplex virus. It causes painful blisters and sores often in the genital area that come in "breakouts." These breakouts are usually preceded by feelings of fevers, chills, and a burning sensation in your genital area. Herpes zoster is caused by the zoster virus which is the same virus that causes the chickenpox. Most of the time the outbreaks occur because the chickenpox virus that you caught when you were a kid reactivate during times of immune system suppression. The blisters and sores that occur because of herpes zoster often occur in a line starting from your back and move to your front. It is certainly possible to get herpes Zoster on your butt. The distinction between these two is usually easy to make by a simple physical exam. I suggest that you schedule an appointment with your primary care physician for further evaluation of this problem. If there is a discrepancy, then your doctor
may send off a blood test to look for exposure to the herpes simplex virus which can give you a better idea of which virus is causing these lesions. Good luck.