And just to confirm, the site of infection remains the area of exposure, therefore my penis should not be infectious right?

Five weeks is too early; wait until 6 weeks for a conclusively negative syphilis blood test. The likelihood of syphilis after a single such exposure probably is under one chance in a thousand. Kissing can transmit syphilis, but rarely. In one way, you are correct that exposure to your penis would not risk syphilis, but that's only because it is very unlikely you have it. If you were to have syphilis, it might be transmitted by genital contact. Syphilis is a systemic infection, and once established infectious lesions may be in many locations, including those not where the infection was acquired.

I stress it is very unlikely you have syhphilis, and if I had I been in your situation, I would not have stopped having unprotected sex with my wife. But for 100% certainly, there should be neither kissing nor sex until there has been a negative blood test result 6 weeks or more after a possible exposure.

HHH, MD

I appreciate your words and educational advice.  When referring to a painless sore, I have a small sore on my inner cheek that somewhat resembles a canker sore however it is painless and that is why my questions arose as it also has a white line going through it through the cheek. I know I should stop worrying, and I understand the likelihood is within one and 1000. 

I took the SCH rapid test approximately 26 days after exposure with a negative result. Would this test also be credible after six weeks of exposure?

There are no data on the risk of syphilis from any single random oral sex exposure, or any other exposure for that matter. I have no idea what sites would try to give a specific numerical estimate. My guess of1 in a thousand comes from a statistical improbability your oral sex partner had syphilis; if they had it, that it was transmissible from his penis even though you apparently saw no penile abnormality; and even exposures to known lesions do not always result in transmission. There also is absence of a typical chancre, despite your possible minor oral sore(s). And finally your negative blood tests so far:  although it can take up to 6 weeks for a positive test result, around 80-90% of newly infected people would test positive at 26 days. My earlier guesstimate of one chance in a thousand now would be a whole lot lower than that, maybe something like one in 100,000.

That completes the two follow-up exchanges included with each question and so ends this thread. Please note the forum policy against repeated question. This being your second, it should be your last about this exposure and your syphilis concerned. However, I'll make a deal with you:  if you test positive for syphilis at 6 weeks, please return to let us know -- and we'll refund your posting fee. In the meantime, do your best to move on with no worries.