I couldn't read and not post
How stressful for you and your partner
I get coldsores on my face and they are so painful and make me feel so unwell. Definitely give your son paracetamol every 4-6 hours and I would also give nurofen every 6 hours as well.
I have never heard of herpes virus being genetic. I got it as a tiny baby from my mum who had an active outbreak at the time.
Good luck with the results, I hope its not herpes