Most developed countries it is rare for syphillis. But it seems like you are worried about it, so in the testing times laid out by AJ I would test for it.
Higher risk maybe? Especially for syphilis?
OK - not sure what China has to do with it, because my advice still applies.
AJ
Well this happened in Shanghai, China. I am male.
2 days is too soon to test for anything.
If you received oral sex, the only stds you need to test for are gonorrhea, NGU (if you are male) and syphilis (and syphilis is rare).
You can test for gonorrhea and NGU at a week after the exposure, and syphilis at about 6 weeks, if you decide to test for that.
If you gave oral sex, you can do an oral test for gonorrhea at a week, and a syphilis test at 6 weeks.
Aj
I would not worry about HIV from oral sex.
Syphillis and Herpes takes longer. Several weeks to a couple of months. Syphillis is rare in developed countries. If you did not notice a rash on the mouth or bump/cancker on the penis/vagina then no real worries.
If you want more detail then you would have to let us know if you gave or received and was it with a man or woman?