I went for a massage and what I assumed was a legitimate massage spa, and was told to fully disrobe. While on my stomach the masseuse kept swiping her hands between my buttocks and brushing my testicles. When I turned over she began masturbating me with oil. I got caught up and briefly put my hand up her skirt, touching her thighs and rubbing her vagina outside of her underwear very briefly. At some point I may have touched my genitals while dressing later on, but before that she had me lay on a “shower table” face down, fully nude. After a few seconds I had the thought someone elses genitals might have been there and quickly jumped up, but it may have been too late. 

Based on your other post, it is too late for that.  In addition, I doubt that there is any risk in this experience for you to worry about, based on what you've said here.---

Even if I’m still in prodrome and no lesions?

I believe it was 10 days acyclovir at 2 weeks post exposure, then a short dose of Valacyclovir at week 7, western blot at week 20, I was off antivirals for 13 weeks at that point

You are posting in two locations.  I have closed the other as you've asked the three questions you are allowed.  And you have my answer - antivirals will not help now, and the dosing for the blot previously has not impacted the results---