Can I get a Chinese visa in Cambodia if I'm American?

I just got my Cambodian visa but now my school wants me in China in February. I can't go back to the US for a number of reasons but one of the main issues is money. A part of my salary is a place to stay in China but it's been almost three years since I've been out. I know it says no for the visa that I have to be back in America but I thought I would ask just to see. Thanks!