I accidentally used a natural colored jelly bean I bought from the credit shop on the wrong creatu and changed it to a less rare color:*( I'd there anything I can do to reverse it?

Unfortunately the only way to reverse it is to keep using beans until it changes back to the color you want. You have to be really careful when using them. The chance of it changing to a color follows the chances of hatching a color (sepia is MUCH more likely than albino) but it can't turn the color it already is or natural, so it's a little easier at least? Good luck!