I am currently living in China. I had been sexually active (MSM) since October 4, and had multiple sex partners (six) I met through an online dating app. I used protection (condom) all throughout my encounters, with four of them giving me blowjobs (unprotected).
After my last encounter (October 23), I noticed a very small spot on the skin of my penis shaft (1mm in diameter). It does not hurt nor does it itch. It is also not swollen, barely unnoticeable, color is close to that of my penis skin which is brown. It almost looks like a scab. It has been there for 6 days already.
Could this be a symptom of primary stage syphilis or any other STD?