I Got my Braces in Mexico, I Wonder if a Doctor Can Check Them Here in USA?

The fee paid is to the treating doctor. Unless you plan to pay an hourly fee for each visit, it won't happen. The original doctor likely wont want someone else meddling with their case, either.  Braces need to be done where you can return every 4-6 weeks.

Of course a doctor can look at your braces. He can NOT do any treatment since you would have to go back to the original doctor who started your treatment. You did not mention anything was wrong with them. You just wanted a doctor to check them. I am assuming you plan to go back to Mexico and have the treating doctor continue with your treatment. You did not mention you were unhappy with the results and there are many good orthodontists in other countries besides the United States. Make sure you continue treatment with the  doctor in Mexico and if you are unhappy with the treatment, you can discuss it with him.

No one here can really be responsible for a treatment started in another country unless they take over the whole case and re design the treatment plan as needed (if there even was one).

What you are paying for with the orthodontist is the actual treatment in terms of time, skill and judgement, not just a hand full of brackets.  You need a Doctor who can make the brackets DO something.   Probably best to travel back to Mexico and hope you get lucky or start over with a new Orthodontist up here where he can design and manage the treatment properly.  It might be good to read some reviews before you start up here also as some of the cut rate Corporate places here are almost as bad as Mexico.  I have seen some really bad stuff from both places.