What you describe doesn’t sound like hsv. Good thing you were smart enough to get swabbed but don’t squeeze or mess with any sores. Just get them swabbed as soon as you se them. A rash covering your upper thighs doesn’t sound like herpes.
Did the girls you were with specifically have hsv tests? An IgG test, the test for HSV, is not normally included in the standard STD panel. You have to specifically requested. Doctors don’t normally test for HSV unless there are symptoms or a patient requests it. Also, the girl who tested a week after her last sexual encounter (before you) would not have been positive on an hsv test if she caught it from a previous partner. The body needs time to build the antibodies to the HSV virus. Most people will test positive on an HSV test around 8 to 9 weeks after exposure. Most everyone will have an accurate HSV-2 test, the common cause of genital herpes, by 12 weeks.
While having a sore does raise a little bit of concern, there aren’t any other symptoms you mentioned that sound like a herpes infection.
Since you have had more than one instance of unprotected sex with different partners, the best you can do is have any sores that show up swabbed. And if so inclined, get an hsv IgG test at 12 weeks.
I am not going to tell you what to do but might I suggest considering using condoms. Condoms do not offer 100% protection against hsv but it does provide some reassurance that you are taking care of your health. Once the hsv fear creeps in, it’s hard to shake. Protecting yourself is the best medicine.