Your motherboard is built up in layers effectively and judging by the picture you've put on, you've removed the resist from the tracks. This means you've removed the protective coating on the tracks.
Realistically, if you're saying you've retried it and it all still works, then you will likely be fine, as a big problem will usually go bang immediately. However if those tracks are connected to USB ports for example, you may need to test them. Using a multi-meter and testing that resistance is equal on either side of the damaged track is a way of testing if there's any critical damage, but if you're saying you've just booted up normally anyway, then that may not be necessary.
But if you're saying it all still functions normally, you will be fine, however to help reduce the risk of future problems, I would clear the scratch marks from any debris, and lightly coat it with a nail varnish to reapply a protective layer.
Again, if you're saying you've retried it and it works, you can count yourself lucky (may cause some future problem) but if you can clear it and apply the varnish now, you can reduce the risk of further problems.
In the future, do not use pliers for that application, and additionally, I wouldn't just try and boot up again afterwards as if you DID cause critical damage, you could also damage other components in the boot up test process. A multi-meter would be best served for testing. You're quite lucky sir!