I had sex with my partner about a week ago. And since then my vagina has been really irritated and itchy, especially around the inside of the lips. I talked to him about it and he said he had a rash around the lower part of his penis. I know this isn't very specific, but we have a long distance relationship and so this is the first time either of us have had sex in the past 6 months. Could this be an std? We were both clean before.