You can prevent spreading the virus by washing your hands frequently. Avoid touching a cold sore and then touching another part of your body, especially your eyes or genitals. "One good way of preventing the spread of HSV1 is to get a prescription from your doctor for an antiviral medication. Taking an antiviral three times a day for just one day may help sores and blisters clear up more quickly," advises Miller. To be most effective, you should start this medication at the first sign of a cold sore, so you may want to get the prescription filled ahead of time to keep it on hand.