Sex with stranger and blisters

I am a 23 year old female and recently had sex with a stranger at a party. Now I have broken out in painful sores on the outside of my vagina. How do I know if this is herpes?

In most cases, an astute physician can make a diagnosis of herpes by the history and physical exam. However, when you go for the physical, the physician may obtain scrapings from the vaginal area and send them to a lab to confirm that this is herpes. There are not many infections that present like herpes and so in most cases, the lab test is not done. Among the STDs, herpes is the most painful.