I used to get freaked over this shit. I've had occasion to test over the years, maybe a penis balanitis or something or other, all turned out negative.
Once checked out Planned Parenthood (> 7 years ago) with blemish on dick, and they said they could give me these tests (clap, syph, HIV, chlamydia) but since I didn't lie on my income in the screening process, they wanted >200 USD donation, funds I could use elsewhere, if you know what I mean.
So, in SF Bay Area, I went to famous Berkeley Free Clinic, stood in line, took a blood screen (all negative), and had a visual inspection, with a couple of dudes checking out my junk because I freaked out because it might be a genital wart (HPV) or a herp (for which there was no test at the time), But they said just might be ingrown follicle or blemish. I went away, but the issue went away too.
Several years before that I went to Kaiser P., my provider at the time, similar situation, had a cute young female asian MD check out my junk, recommended the panel (clap, syph, HIV, chlamydia), all negative, she referred to dermatology, he said probably hair follicle issue. No worries, it went away quickly.
Hey, someday my day of reckoning may come up, but it's been all false alarms.