The best way to dry your paco out would be to get the foam out. Either cut open the material right by the flap with the grommets and the pad or you can use MEK to release the weld. This was the last weld done during its construction. Once the material has been opened up, pull the foam out. You can either dry that foam out or order a more dense foam that will offer more support. Sailrite.com is a good source for excellent marine grade antimicrobial foam. Once you have your desired foam insert it back into the material sleeve. Now comes the fun part! Welding or glueing the opening shut. If you cut it open you will lose a little length to seal it back up again. If you used MEK and a putty knife to break the weld then you can weld/glue the flap back together. THE MOST IMPORTANT PART REGARDLESS OF YOUR CHOSEN METHOD TO CLOSE IT IS TO CLEAN IT!
If both surfaces are not properly cleaned neither the weld or glue will hold very long. Isopropyl alcohol will clean the surface sufficiently as will MEK.
I would recommend glueing it since you're not familiar with welding PVC. PVC burns up really fast under the gun, turns black if over heated, and stinks like no other.
Good luck and keep us posted on the progress!
There is no such things as bad weather......... Just the wrong gear!