Shine Amuse Rear Odd Issue
 

So quick question to those who have the bumper or those who have seen this bumper. I had it installed its great but I have a big issue. Everytime I wash the car, water collects inside the bottom lip of the bumper and I can not get it out. You can see it pool in the very inside corner of the bumper inside the rear wheel wells. Each side has an opening where you can see the suds flowing to.

I really do not want to leave it filled with water, and furthermore when I stuck a paper towel in to sop up the mess it came up with all sorts of road gravel and crap. So other stuff is getting in there. How can I remedy this situation?

I have had two thoughts so far. Expandable waterproof foam?? Could this expand too far and warp the bumper? or crack it?

And or Drill small drainage holes in the bottom of the bumper? Yet this wont stop unwanted road grime getting inside the bumper.
Anyone else have any suggestions, any advice or expertise is welcomed.
Thanks guys!

I would probably drill.