Hi Horriblelife, (I hope it's not that bad!)
It sounds like you're pretty nervous about this. I'll try to be as helpful as I can, okay.
If several doctors have looked at you and each have given you a different diagnosis (or a non-diagnosis), I'm not sure any of us can bring you much closer to really knowing what's going on with you. Each of the doctor's diagnosis are plausible but your best answer will come from an antibody test for herpes as it can confirm or deny that diagnosis pretty easily.
If the herpes test is negative, it can give the doctor some direction to look at other reasons for the lesions. Here is some information about molluscum that may be helpful as well:
symptoms of molluscum are lesions that can be found on the thighs, buttocks, groin and lower abdomen of adults, but may occasionally appear on the external genital and anal region.
The lesions may begin as small bumps that can develop over a period of several weeks into larger sores/bumps.
The lesions can be flesh colored, gray-white, yellow or pink.
They can cause itching or tenderness in the area, but in most cases the lesions cause few problems.
Lesions may recur, but it is not clear whether this is due to reinfection, exacerbation of subclinical infection, or reactivation of latent infection.
I know you're going to another doctor this week so I hope he/she can tell you what's really happening. I'll be here if you have other questions.