What kind of a show is it and what is your goal? If it's a juried show and your goal is to win first prize, you may want to fix the worst ones. If it's a smallish local un judged show or a juried show and you are not looking for a prize, just the experience, I'd also just continue on. Personally, they look good to me.
I have had lots of experience ripping, however. If you do decide to fix some of them, start by re ironing the seam so it's the same as when you sewed it (not pressed to the light or dark). Using the point of your seam ripper work on one side or the other, cutting every 3rd or 4th stitch. Turn the piece over and you should be able to remove the entire thread. Now separate the 2 pieces. Do not tug or pull on the patchwork. Unsewing this way will result in the least amount of distortion. I have never had any luck with just removing part of a seam (unless the error is when I'm joining rows).