Crispy motor shield

I have a L298-based motor driver shield that had worked properly until there was an, ahem, "mixup" in wiring and I got the magic smoke. Actually, it seemed to continue working after that, but upon changing to a different configuration (which I checked and double checked so I'm pretty sure it was OK) I got some more magic smoke and an obviously burned trace on the PCB.

So my questions are:

  1. Could the initial incident have 'weakened' something but not destroyed it so that the board continued to work?
  2. Is it possible that the 'weakened' component could then have failed and caused the burned trace, even though everything was connected correctly?
  3. Is there any point trying to fix the trace?

Yes, yes and what do you have to lose?

Yeah I guess I can afford the $0.00001 worth of solder and wire. Any good resources out there on how to fix burned traces?

Clean the ends of the trace at the break so the copper is bright (I use Scotchbright or fine emery paper). Tin the cleaned areas. Lay a piece of tinned wire of appropriate gauge across the break and sweat in place. Clean the rosin flux off with alcohol.

Is there guidance somewhere on 'appropriate gauge'? I'm assuming you want something of relatively equivalent resistance, but I don't know what the tolerance would be.