Passport Problem Regarding Re-entry to the US after going to Mexico.?

Question

I am a Singapore citizen and I flew from Singapore to Los Angeles. Thus, on my passport, i have the US visa stamped from LAX when I reached LA. After that, i traveled to San Diego and crossed the border to Tijuana via Greyhound bus.

Currently I am in Tijuana and I will be flying to Guadalajara tomorrow and will stay in Guadalajara for 1 month. After that, I will fly from Guadalajara back to Los Angeles before flying back to Singapore from Los Angeles.

However my passport didnt get stamped by any US customs to certify that I've left the US for Tijuana today. Will I face any problems from the US customs when I fly back to Los Angeles 1 month later from Guadalajara?

The locals told me that passport dont get stamped at Tijuana unless i leave Baja California. They told me to inform the Tijuana and Guadalajara customs about my situation at the airport. I dont know how true is that.

Can anyone help me?

Answer 1

My boyfriend has come to México (south of Tijuana) with a Malaysian passport after landing in San Diego.  He always had his I-94 (is that what it's called?) and it was always fine going back to the States.  

The only thing is that since you are going further into mainland México... that might be an issue... sorry i can't help you on that one.... and have fun :)

Answer 2

you shouldn't have a problem. you have your passport and that verifies your citizenship, if you explain you arrived via bus you shouldn't have an issue.

Answer 3

I have not had my passport stamped in years and travel all over