A related discussion, Hep B Vaccination was started.
First, I am sure you can rely on the safety of the heptatis B virus (HBV) vaccine wherever you are. Even the products used in developing countries are reliably produced and have never been known to cause any health problem. Personally, I would not hesitate to be vaccinated against HBV anywhere in the world, as long as I knew that the needle and other injection equipment were sterile and not previously used.
A single dose of HBV vaccine confers very little protection, if any. Moderate protection results after the second dose, but all 3 doses are required for complete protection. However, the timing of the subsequent doses isn't all that important. Dose 2 should be at least 2-3 weeks after the first dose, and dose 3 should be at least 2 months later. Otherwise, almost any schedule works; you could have dose 2 and 3 any time over the next 1-2 years and probably will then be fully protected.
HBV is acuired only through blood contact or sex. Indeed, it is much more contagious than HIV, but still not contacted through the sorts of contact you describe.
Bottom line: Finish your 3-dose HBV vaccine series, wherever you are. If you aren't reassured by my comments about developing countries and their vaccines, get doses 2 and 3 if/when you return to your own country (which, I am guessing, is China or in SE Asia) or to another industrialized country. But you should consider yourself entirely unprotected until at least your second dose.
Good luck-- HHH, MD