Thank you Dr., I appreciate the timely and informative response. Take Care
Welcome to the forum. Thanks for your question.
You say nothing about your "old acquaintance's" sexual lifestyle. If she gets it on frequently with casual partners, obviously the STD risk is higher than if this was equally out of character for her as for you.
But even if she had an STD, it isn't the cause of your symptoms. First, they started much too soon: no infection, STD or otherwise, can start to cause symptoms in 7 hours. Two days is about the minimum. Second, there are no STDs that start out as skin rash of the type and location you describe, or that cause cough or sinus symptoms. Your urinary symptoms are typical for genitally focused anxiety, which can cause elevated bladder muscle tension and is extremely common in people with an "overwhelming sense of shame" (your words) over a regretted sexual decision.
If your symptoms continue or you otherwise remain concerned, getting checked for STDs makes sense, if only for the reassurance expected from the negative results that you can expect. But please don't waste money on an extensive panel that includes tests for infections for which you were not at risk. It would be better to see a doctor or clinic with experience in STDs (e.g., a health department STD clinic, Planned Parenthood, etc). Any testing can safely be limited to urine for gonorrhea and chlamydia, and blood tests for syphilis and HIV. (The last aren't valid until 4-6 weeks after exposure; don't waste money on testing before then.)
I hope this has helped. Best wishes-- HHH, MD