Hello, and i hope I can help you today. First, I want to reassure you that no STD causes symptoms within hours or even a day after exposure. So you do not need to be concerned about the itching and discomfort you are experiencing being symptoms of an STD. You certainly can chafe or bruise yourself if you continue to have sex while not being adequately lubricated, especially if it becomes painful. The chafing can cause soreness and the irritation of the delicate skin near the vaginal opening can cause itching. Furthermore, if you were using a condom, you could also be sensitive to the latex or spermicide in the condom. I suggest you soak the area in warm water at least twice daily and apply a 1% hydrocortisone cream (sold in pharmacies to treat itching) to the area twice daily for 3 days. If the itching has not resolved or if you develop discharge that is foul smelling or heavy after 3 days, you should see a GYN doctor to see if you have deveolped a vaginal infection (not sexual). In the meantime, I suggest you refrain from further sexual activity until the swelling has resolved. To help prevent this from happening, using a lubricant if you want to have sex before your natural lubrication has fully developed can reduce chafing and also make intercourse more pleasurable. If you use condoms, purchase a brand that does not contain spermicide as many women can be allergic to the spermicide. I hope I was able to answer your question today and that my advice was helpful. Best wishes, Dr. Brown