Flea beetles will also eat holes in the leaves but I wouldn't think they would be active now. Cucumber beetles will eat holes but usually in the blooms.

If you can't find any more slugs then I would treat the plant with a little Sevendust of if organic is your preference try insecticidal soap. I wouldn't use Seven on the blooms as they could turn the petals brown and I have no experience with the other in that regard.

I'm always surprised when messages point out how they were able to take dahlia blooms inside to decorate their vases.
I make a habit before they go in doors, they go in....water..upside down for a time that makes the bugs that are in there to come up for air. I'm surprised when a flower comes up without having an unwelcomed guest in it.

The usual trap should be part and parcel for earwigs---they like it damp and dark.

There were about 4-5 of them on one of my plants and insecticide doesn't seem to faze them at ALL... ARG! They have eaten so much into my plants that the limbs are breaking in addition to them simply eating the leaves.

Then once I got that under control the Japanese beetles came to eat on the buffet as well. I sprayed them with my soap and water solution but then the bloom would turn brown. So, on go the gardening gloves so I could squish them.....I hate squishing them but I love the flowers more. LOL.