How do i get my luggage when i dont have a chinese visa and im staying for less than 24 hours?

Im a US citizen and i can still enter china quite a bit of times, but im traveling with my mom who is a Mexican citizen, whom only has 1 entry.

We are already in china and we have a flight back to the US on the 12th. We want to spend a week in Japan and then go back to Guangzhou the day of our original flight in time to go back to the US.

Im wondering how we are gonna travel with our luggage. How do we retrieve our luggage if we cant enter china again??
Basically just how can we make this work?

PLEASE let me know!!
Thank you.