Is it possible to have herpes if the swab came back negative?

[Flea]

I'm almost 39 weeks pregnant and around 34 weeks I went to the hospital because I had a painful itchy rash on my vagina. They said most likely I had herpes and to follow up with my dr. The following Monday I went to my ob who did a culture of the area and took some blood. They went ahead and put me on Valtrex to be safe. They called back and said the culture can't back negative for herpes but my blood showed I had HSV-1. They said they wanted to keep me on Valtrex to be safe. I asked the dr if this meant I had genital herpes and he said he could neither confirm nor deny it. Since the initial "outbreak" I've had two others while being on Valtrex. All in the same spot, but they don't last as long as they used to and their not as painful. So is it possible that I have genital herpes even though the culture came back negative? I had already had the outbreak for almost a week before I went to the dr. I don't know what else it could be.