Beginner Gardening: What's eating my dinnerplate dahlia leaves?, 2 by Lyssa13

Lyssa13 wrote:
Help! I have two potted dinnerplate dahlia plants that bloomed beautifully when I bought them. However, they are now sad and the leaves are all eaten with holes.

Based on these pictures what do you think it is? What do I do to fix it. And will my plant come back alive once I fix it or is there a chance it's dead?

Help, I'm very much a beginner at this and trying to learn!

Whatever this is hasnt touched anything else in my backyard, just the dahlias.