Sawfly caterpillar. I've been spraying mine with dish soap and water. Otherwise squishing em works.

The bottom half of mine are leaf free. Otherwise they are still in bloom.

Hope this helps.

Isn't is frustrating? It happens every year nonfail. If you spray them right away you can catch them before it gets too bad. Then they look so sad by the time they go to seed I try to immediately cut the seed pods off so they put energy into growth instead.

Does it look like little tunnels? If so it is leaf borer. It doesn't hurt the plant it just makes them ugly. This happens to mine that are in the sun, but not the ones in the shade. I don't know why. Anyway, I read that if you cut them back they are supposed to grow new nice leaves and the leaf borers are then gone.