So you aren't neurotic, but the doctor is.
Yes, syphilis has been known as the "great imitator", but syphilis is uncommon in developed countries, like the US, Canada, UK, countries in Europe, etc.
Testing everyone with any kind of anything is overkill and fear mongering and a waste of time and resources and health care dollars.
In any case, you don't say when your most recent exposure was, or how long after it that the spot appeared, so I can't say how accurate the test was. Do you know what type of test you had done? That would also help.
How long did you have the spot? How long did it take for the cream to work?
Chances are excellent that this isn't syphilis, but I can't give you more definitive info with the info you've given.