There are 3 antivirals (oral
medication) generally prescribed for treating HSV. These are Valtrex/valacyclovir, Famvir/famciclovir, and acyclovir. They require a doctor's prescription.
There are also several topicals that you can get over the counter. Some of these are Abreva, Releev, and Dermoplast.
In addition some people use natural remedies such as honey, which has been found to have antiviral properties.