Bernie,
Here is what I would do. I would use the flush rivet squeezer set in your pneumatic squeezer to squeeze out the "bad dimple". This will make the flange of the spar flat again. Inspect closely for any cracks that might of formed. If there are any cracks, stop drill them. Debur the new hole and dimple the intended hole. Make a doubler shim out of 0.032 and put a hole and dimple in that. The doubler will go on the inside of the flange of the spar, while the skin will be on the outside of the flange of the spar. Obviously, use a larger rivet to accommodate the doubler.
Good news is you put the extra dimple in the spar and not the skin, so when its all together there will be no visible damage.
Good Luck!