How do I extend shower cover plate without replacing a tile
Check with the manufacturer for parts for your model #. They might have a larger cover plate. You could also bring it into a plumbing supply store and see if they have a larger one. You'd be amazed at the parts a good plumbing store has. Last but not least, there is usually a bead of white caulk around cover plates in showers this color. A good bead might just cover that opening if all else fails.