I did the same thing! It wasn't my cat -- it was me. The hole is above the water line. Do I have to fix it? The toilet seems to work better with the hole in.

Hi marionjae and Welcome to The Plumbing Page. At AskMeHelpDesk.com. You're responding to a 3 year old dead thread so I gave you one of your own. Look in then upper left hand corner of the first post form the date in the first post before you post, Thanks,
If you leave the hole open it will reduce the force and volume to the jet. Patch the hole with Epoxy. Good luck, Tom