Its too early to tell. There's a lot of conditions that look like herpes including balantitis, scabbies etc. Im going through something similar and all ive been doing is researching and obsessing over it. I have to wait a few weeks to take a IGG type specific herpes test. But its always more accurate to get it swabbed so they can identify the virus under a microscope. If u have any other lesions/blisters, go to the doc asap so he can take a swab. Otherwise you'll have to wait at least 3 to 6 months for any blood work to pick up antibodies to confirm results. Keep us posted. We're all here to help support each other. A lot of us are in panic believe me
How can it be herpes if you tested negative smack in the middle of what you suspect is an outbreak? The IgM test is useless, admittedly, but the pcr swab when lesions are present is the best test available. Photos don't look like typical herpes either.
One day of medication should have no impact. Pcr is very accurate, so long as adequate virus is collected, whether from "bubbles", skin or whatever. If you are worried, get tested again (ask to break open a bump) and/or do the IgG blood at 3+ months (not IgM).
It needs less virus to test, so there's a good chance your lesions will still have enough. Select one of the more recent, larger ones. If you get bumps again in future, pcr swab immediately. If not, follow-up with IgG at 3+ months. That's what I would do if i were really worried.