Shot images on a dirty SD card, HELP!

Even though I keep my SD cards in a pocket made for SD cards, IN my camera bag…I managed to shoot a session with one that had something stuck on the gold pins and only 1 out of the 450 photos aren’t corrupt. During the session I was able to show the clients some back of camera shots, so I’m thoroughly confused. We gently cleaned it off, photos that I took AFTER the cleaning are showing up but no free recovery software is able to get the images from my session to show up. The files are “there”, both NEF and jpeg but when I click them, it says it can’t read them. I’ve tried viewing them on my camera, my desktop, and with a card reader.  I’ve already done check disk in commands and I’ve done the check through the properties and both yielded no results. Am I screwed or would a paid software be able to get these files to open?