The corrosion is due to the dissimilar metals (aluminum side sill and steel frame) in contact. Being wet "may" accelerate the process, but is not the cause. The fix from Dodge was to use the galvanized side sill screws because the galvanized surface acts as a sacrificial metal in the corrosion process. (I guess that means you should replace those screws periodically.)
The real cure is to keep the aluminum from touching the steel. Usually the paint would do this. I have had surprising good luck (~10 years on replacement set) by placing duct tape on the steel body and on the inside of the sill, where the two would make contact, before reinstalling. I also used Home Depot sheet metal screws that come with captive sealing washers (steel washer with rubber washer insert.) Think of the idea as electically isolating the side sill from the car.
I'm not a paint expert, but would think that sanding, prepping, and repainting the sill would fix the bubbles. Then you need something like the above description from having it happen again.
You would think the engineers would have known - this issue is what ate up original Cobras when the aluminum panels were riveted to the frame.