A few things:
In order to communicate with an ODrive board you must supply power through the main board power connectors at the same time you are trying to communicate it over USB. To be crystal clear: In order for your ODrive to appear on USB you must have it connected with a USB cable to your computer and at the same time be supplying power through the main DC power port.
The 3.26V difference between TP2 and TP3 doesn’t mean anything. TP2 is attached to the USB data line so it will be constantly switching between zero and five volts whether or not your ODrive is doing anything. To actually derive meaning from that test point you will need an oscilloscope and hopefully a protocol analyzer.
When you first connect your ODrive to power it is normal for there to be a spark due to the large capacitors on the board rapidly charging. Based on some measurements I took with my multimeter the USB shield is connected to ground just like the negative terminal of the main power port so I feel that it is unlikely that contacting this area would damage your board.
The only failure scenario that I could think of would be if you somehow managed to touch one of the USB data lines with the negative terminal of your power supply. In this case you might have damaged the main microprocessor chip on the ODrive. It could be replaced but you would need a hot-air rework station and you would need some way to reflash the ODrive firmware onto the chip once you attached it to the board. I think it would be quite unlikely that you somehow managed to damage the USB port itself. If you did there would be visual damage that you could see with a magnifying glass or a microscope.
In summary I think it’s unlikely that your ODrive is actually damaged. Be sure that you are powering the ODrive through it’s main power port as you are trying to communicate with it over USB. Also verify that the USB cable you are using is good. The world is becoming increasingly full of shitty USB cables that will transfer power but not data. Finally check in your operating system’s device manager or equivalent to see if your operating system can detect any sort of USB device at all.