By "fix", I'll assume you mean return to the stock look...
Back in the day, Sherman & Assoc made or sold patch panels, but:
I don't know if they made Dart/Scamp ones
I don't know if the contours were right
and I don't know if they went up as far as you'd need.
But, there are lower skins I think, and probably full quarters by now.
Might even be some clean used quarters somewhere.
Gonna need to stretch the opening for big tires, I know...
Side note: some tech guys really dislike side-mounted kill switches; I had a similar deal using the L/R side marker, and they encouraged me to relocate it to the rear of the car.
The thinking is, if the car's against a wall, a side-mounted switch is too hard or maybe impossible to get to.