I think the best you can do is build up that area with polish. I've seen some pretty impressive results from guys like @Crat who beat the hell out of their shoes. I'm no expert, so hopefully he'll chime in with some words of wisdom.
I don't believe much can be done to repair where the leather is actually gouged away, but a few good coats of polish should restore the shoes to presentability. Remember that at the distance people will actually viewing your shoes, that little gouge will be all but invisible once it has been concealed with polish.