still worried about syphilis

Doc
You responded to a previous question of mine & I was very appreciative, however I'm still worried about my condition. Recap: went to massage parlour, performed unprotected cunnilingus on girl and protected vaginal sex. 2 days later I went to GP with 'flu-like'symptoms, turned out I had Strep throat. I asked if my condition had anything to do with my recent sexual encounter, he didn't seem to think it did.  He gave me 3 tablets of Zithromax & said that should take care of the strep as well as any bacterial STD. 7 days after sexual incident, I noticed a discolored spot on my upper lip that looked like a blister & began worrying about Syphilis. You responded that syphilis was low risk for the encounter I described. However, its been 4.5 weeks since I noticed the spot on my lip and its still there. It is about .5 centimeter, maybe smaller. It looks like a blister or sore that is almost healed, but it looked like that from the beginning, it never looked like an open blister and never bled or hurt. My concern is that its still visible, although I have to look a little closer in the mirror now.  It does not appear to have sharp or raised edges, and when I slightly stretch my lip it appears to be just a flat discolored (whitish/pinkish) spot on my lip. My question is should I go and get tested for Syphilis, or is my risk low enough to not even warrant testing? If I do test, how long should I wait and how long will it take to get results? Also would the Zithromax have been effective against syphilis had I gotten it? Your advice is so helpful and I'm so greatful for this service

[H. Hunter Handsfield, M.D.]

I don't think you need testing; your risk of syphilis is about zero.  But if you'll sleep better if a blood test proves, go to your local health dept STD clinic and get tested.  Azithromycin is highly effective in preventing syphilis, but not perfect.

HHH, MD