An itchy and swollen vulva can happen for many different reasons, so we can’t give you a definitive answer. Sometimes your body has a reaction similar to an allergic reaction when you have sex with a new partner because that person’s bacteria, yeast, pH, and other factors are different from your own. You may also have had a mild yeast infection, which generally causes itching and some swelling. Yeast infections can go away on their own, but sometimes you do need medicine to fully get rid of them.
If you had unprotected sex, we strongly encourage you to get tested for STIs. In general, it’s best to wait a few months before getting tested, since many of the most common STIs take an average of 3 months to show up in your system. If you get tested immediately after having unprotected sex, it’s possible the test results won’t be accurate. Remember that you can get tested for FREE at Teen Clinic, and it’s totally confidential.