yes, you can actually go check the voltage on your controller while it is plugged into your battery. with the hall sensors and phase wires still connected
you will see places on the pcb where they have +5V printed next to pins and holes in the pcb.
you can put the voltmeter on there, black lead to ground, and it should read 5V.
if not then you have a problem with the power resistor that got all discolored when it burned up. it burned up because somehow that resistor leg or maybe the edge of the pcb where that trace is, touched the case and shorted out the full battery voltage, so that resistor reached high enough temperature that the inside turned into plasma and the heat from that plasma discolored the inside of your box.
i suspect if you replace the resistor with the proper one, or even a little higher resistance, your voltage regulator will work again and your controller will behave again. make sense? other things coulda burned up, check the second resistor too, but it does not look dead. just close, so check it anyway. that is where you can read the 12Vbus too i think. across that 2nd resistor.
you really should make a plastic cap / tray to go around the end of the pcb there. like i said, a small polyethylene plastic square that includes the corner of the jug a little, around the end and underneath it for long term prevention. also cut off the long legs of the new resistor too.
before you put the pcb back inside, test the 12V and 5V before you put it back inside the box and if you get those back at normal, that is likely all it is. but i'm just guessing.