The antivirals that you’ve taken MAY be interfering with antibody development and giving you a false negative IgG, if I’m reading the timing correctly, but it all depends on sexual activity around that time. I would recommend that you consider coming off the antivirals and retesting in a few months. However, if you are having sex with someone who is uninfected, and you do have genital herpes, this puts them at greater risk of infection.
Biopsies cannot tell actually if you have HSV 1 or 2 or even if this is herpes simplex. Biopsies would look for something we call multinucleated Giant cells that are present with shingles infections as well. you case is really confusing to me, honestly