Apple watch series5

I got an Apple Watch series 5 GPS Aluminum Case as a new year gift which was bought from The US. I have had a good

experience in using it. However I get some troubles which are Unresponsive microphone, some rustic strain on the

case, and the power button is hard

to turn off. Unfortunately, Apple store in the country where I live

(Thailand)does not allow me to fix the Apple Watch which was bought the US. How

could I get it fix outside the US? Or I should buy a new one. What does Apple

suggest me to not have the same troubles again?

Thank you