Hmmmm. Blisters are never really good in the genital area. But what you describe as a blister and I might describe as a blister could be different.
Two days is not too soon to develop symptoms, no. It is on the low end but I’ve seen it before.
I have to say that it is interesting that all four women with whom you had sex had done HSV antibody testing – that’s kind of unusual. Sometimes, people think a full STI screen includes herpes antibody testing but it often does not. Have you actually seen these results from all four women? It is also unusual that all four women would be negative for HSV 1 when half the population is infected, but it could be, certainly.
If you were my patient, I would recommend antibody IgG testing at 6 weeks out and western blot testing at 12 weeks out.
But if you continue to have sex during that time period, it will always be a moving target. Condoms reduce transmission of HSV 2 from women to men by 65%.