Question about an unusual skin condition that timing-wise is troubling to me. First, I was involved in a number of acts of MSM oral sex, both giving and receiving.  I am on PREP, doxypep abd mpox vax.  However, there was recently an outbreak in my area of mpox.  After this, I noticed the bump on the sidewell of my nose, about a 1/3 of the way up the left side of my nose.  Maybe 1cm up from the bottom of my nose. I admit I was touching it a bit. However,  it started to grow, and then within another couple of days had turned a grayish color.  It then started scaling.  I touched it and a piece of it fell off.  I had just taken some doxy at this time for another incident.  It started to recede, and is now just a  barely noticeable bump about 3 weeks later.

Welcome back to the Forum and thanks for your questions.  I happened to be on the Forum when your questions arrived so you are getting a reply sooner than is typical.  Follow-ups may take longer.  ---

So in point 1, when you say transmission is promoted by abrasion,  what exactly does that mean?   Is it that a cut or open sore would need to exist for transmission to occur in that area?   The thing is I can't be sure there wasn't direct contact with that part of my nose during the oral sex. However, I am pretty sure there was no open sore there.

My last question, since I have your attention.  The 2 hour rash wouldn't be consistent with ARS either,  correct?   I am on PREP but my only concern (which was mild but still there) was that I had a couple pills in a hot car for about 5-6 hours when traveling so I was worried those pills were damaged and my protection may have been diminished during that time.   I had oral sex the day after the car incident and I doubled up on pills so I still had 6 out of 7 for the week.  So not too worried, until if course, there was the rash.

Friction is a part of all sex.  There does not have to be an obvious abrasion or open sore.---

I got tested today and am waiting for results.  I felt good after testing but now am nervous.  

While the rash of secondary syphilis is highly variable, the transient blotchy rash of the sort you describe is really not suggestive of secondary syphilis. Further, the doxycycline you have taken would almost have certainly prevented Syphilis if you had been exposed. Once again, I heard you did not worry---

I hate that I am back.   I did get a syphilis test 5 weeks after my last incident and it was negative.  However,  literally less than 2 days later, I got a big whitehead/pustule just above/touching my upper lip.  It shrunk rather quickly and a day later is just a small (less than .5 cm) sore/discoloration whitish/yellow in the middle and a little red around it.   It is hard to see because I have a beard.   From my understanding,  a 5 week test isn't completely conclusive and it is also possible that a test could be negative when the primary chance is just starting.  I know this isn't a typical presentation but I can't recall having a skin issue like this and the timing seems right.  I just keep thinking why am I getting these weird skin symptoms now.  Also, I did take doxy pep. Could that cause symptoms to be unusual if it failed to eradicate the disease? To completely rule out this new sore as a chancre,  would I need to wait until it is a full 6 weeks post incident or would the test turn positive earlier due to the presence of the sore.  I feel a little insane going for another syphilis test just a few days after the last one but a potential symptom is a symptom (at least that is what my mind is telling me).

Final response.  Thanks for posting your test results- they PROVE that you have not acquired syphilis.  The lesion on your lip sounds nothing like syphilis which does not form solitary pustules of the sort that you describe.  Further your risk was low, the timing is wrong (the typical time for presentation of primary syphilis lesions is less than 3 weeks- you're at 5), your doxy-PEP makes your risk close to zero and your tests are negative when nearly all persons with syphilis would have positive tests.  If you are looking for answers regarding syphilis- please stay off the internet- it will only fuel your unwarranted paranoia regarding syphilis regarding every blemish, bump and pimple you find.---