Unfortunately, I think your physician mishandled this situation, at least from your description of events.
What should have happened is that the lesions should have been swab tested. Was that done?
A blood test taken at a first infection is always going to be negative because the blood test looks for antibody and with new infection, there will be no antibody present. Do you know if the test was an IgM or IgM test? The only good test is an IgG test. Were you given antiviral medicine? If yes, did you take it and for how long?
Sometimes a bad yeast infection can cause white dots as well.
All you can do now is wait at least a month to do another IgG antibody test or if you get more of these lesions you can ask them to be swabbed. A final antibody test should be taken at 12 weeks post exposure. You might also ask the person with whom you had sex to get an IgG test for HSV 1 and 2.