That's the misconception about reading hsv symptoms. The first thing you will notice from a primary is lesions forming. Not nerve pain or any of the other symptoms people think signal a primary outbreak. Those symptoms are for future outbreaks past the primary. So lesions forming and flu like symptoms are what to watch for.
At 8 days though it's looking good that you did not contract hsv
Not sure I understand your question
In my experience it's due to stress and being overly aware of the area. In all my time doing this is have never had someone with your symptoms come back saying it is an std of any kind.
There are no stats for the exposure you had. Not many studies have been done on the subject. No money in it. Most exposures do not lead to transmission of the virus. Yes it is a bigger risk when a cold sore is present but what stage the cold sore is in matters as well..was it all scabbed over or an open sore? If it was scabbed then your risk was lower as the virus would be retreating by then.
If you do not have an outbreak by ten days then I would say you are 90% in the clear. A newly acquired hsv1 genital infection are rarely asymptomatic.
12 weeks would be the proper time to test.
It is higher risk if it indeed was a cold sore. If you did contract hsv1 on the genitals you will most likely have a very noticeable primary outbreak 3-10 days after this encounter.