I guess that as long as your category is not asylum based (with just slight risk when entering US since that category is for people who can not return China, but crazydog said that he knew people who used it to go home), then you could still use it, and file I-90 to replace it after you are back here. Here's a case that one person realized that his category was wrong only after he entered US in the port. http://www.visajourney.com/forums/topic/308277-wrong-green-card