Welcome to our Forum. Your risk for any STD, and particularly syphilis from the exposures your describe is very, very low. Few STDs are spread by oral sex and you used a condom for your vaginal exposure, reducing your risk in that situation. Your condom was fine if it appeared intact upon completion of intercourse. Condoms do not fail by leaking a little, they break wide open. Thus, if the condom appeared intact, it was.
1. Your risk for syphilis is extraordinarily low. Had the lesion you described been syphilis it would not have appeared so soon following exposure and would have gone on to ulcerate with the sore last several weeks. Further, statistically, syphilis is VERY rare in North America. This year there will be only about 10,000 cases of syphilis in our nation of over 350,000,000 and about two thirds of those will occur among men who had sex with men. I have to disagree with the doctor who saw you however, a syphilis blood test likely would have been useful at the time you saw him. Blood tests are typically positive within a few days of the appearance of a lesion. Further, to address your question, a blood test at this time would certainly be reliable.
2. See above, the probability of syphilis was low. I doubt that he though syphilis was a realistic possibility. I do not.
Diarrhea and sore throat are not suggestive of syphilis. they could arise from bad food or, most likely at this time of year, a flulike viral illness of the sort we all get from time to time.
I hope you find my comments useful. EWH
Sorry, we have a policy not to look at pictures on this site. Too many bad expereinces related to mis-interpretation. Better to have your own doctor take a look.
I would not worry about syphilis if I were you and would not worry about the need to abstain. EWH
Thanks for your speedy reply Doctor. Would it be safe to say I can have unprotected sex with someone of known 'clean' STI status in your opinion?
Or do you think I should wait until I get a definitive test.
Just to confirm that I'm in Western mainland Europe not the US (I ran out of characters to type in my initial post :) )
I can even send a picture of the spot if that's possible here?
Thanks again