Problem with the ports

I was calling 3 stepper motors in the arduino, when a colleague reversed the wires of the source plugged into the CI, so he threw the port 12V. I noticed that the engine was no longer driven by these ports, I took a led and started to test port by port, and I found that 12 ports that were being used can not play more than 2.5 V on digitalWrite "HIGH", the 12 ports PWM are just, I have an Arduino MEGA 1280. Do the doors have been burned?