Can parts that have warped (after being printed) be un-warped?
PLA stays a thermoplastic in printed shape. And as you saw when unpacking your things, tropical heat and force are enough to get a lasting deformation. Other people had PLA prints ruined from having them sit in the car, I had seen deformation on a purple print I had let sit in the sun on an edge.
This also means that the reverse is true: under load to shape the part and some heat you can try to unbend parts. A hairdryer air of about 60-80 °C, which is more than enough to make PLA formable.