If you have genital herpes, it is important to always use condoms and dental dams when having sex, even when you have no symptoms. A dental dam is a square of thin latex that can be placed over the vulva or anal area during oral sex. It is safest to avoid sex when you have blisters, sores or symptoms. It is also important to tell your sexual partners that you have genital herpes. Your doctor can help you decide who to tell and how to tell them.