For syphilis, you would expect a sore to occur at a site of
infection within 3 weeks of exposure and then
for a blood test to be positive by about 4 weeks after the exposure. If there is no sore that develops, the chance that the blood test would be positive is about zero. Further, the antibiotic you took would prevent syphilis. I would not worry about syphilis.
3. what are my odds of catching Syphillis give it is more prevelant in SE Asia and Thailand.