You're welcome. Happy TG to you as well.
Thank you for your reassuring comments. Have a Happy Thanksgiving!!
Welcome to the STD forum.
Syphilis is rare in most industrialized countries. In the US, there are no more than 20,000 new infections per year, and two thirds of those are in gay men. So on statistical grounds alone, the chance you were exposed to syphilis is very low. Second, the lesion you describe doesn't sound at all like syphilis. Finally and most important, a negative syphilis blood test more than 6 weeks after exposure is proof you were not infected.
From your desciption, this sounds most like a pimple or folliculitis (hair follicle infection). If it persists or others appear, see a health care provider. But for sure it isn't syphilis or any other STD on account of your August exposure.
Best wishes-- HHH, MD