Jj kit, you will need to fix the corrosion cause 1st then repair or cover up.
I have this on my 54 Cruiser. Mine is on the belly pan panel which will be replaced anyway with my shell off resto.
Ensure it is corrosion or wear. Mine looks more like wear due to failure of the bond of the panels and the floor in the area. And some corrosion.
Either way, the aluminum is touching the outrigger which is where the corrosion is occurring and the wear due to movement.
Again, resolve the issue before covering it up. Also, check the structure between the floor and exterior panel.