Did you ever figure out what this was? Please, it would help me so much. I have something very similar to you and have gone through very similar circumstances. Also, if you didn't find out what this was did it go away on its own or do you still have it?
Lets say when I was in Amsterdam I made a huge mistake. I felt itching in the groin area for months and felt it right away after the incident. Was it guilt, probably, but then again, 7 years later I have genital warts. Could that mistake 7 years ago started the genital warts, who knows, does the itching you have is genital warts, maybe, but most likely its GUILT and ANXIETY. I made another great mistake over 2 years ago. Anxiety cause so many problems, headaches, muscle aches, lymph nodes aches. I got check for STD's multiple times all negative, but it did put me through hell. Remember you might be infected with HPV for years and not show symptoms, or might be caring it and never show symptoms, HPV doesn't cause itching. THIS IS YOUR GUILT AND ANXIETY! But never rule anything out, get tested in a YEAR!