I doubt if your plant will grow again. Canterbury bells are prolific self-seeders. They typically drop seed in the summer after the blooms form seed pods, bloom the following spring, and then die.

If you get another plant, make sure nobody cuts the bloom stalk off before the seed matures.

I cut my canterbury bells back every year and get a second flush of blooms, just smaller.

I cut them back all the way to the rosette.

Well, doesn't it depend on what kind of campanula it is? I have some that are perennial. Or, at least, the same plants come back for me every year, in the exact same spot. I think they are persicifola.

What do you mean by "to the dirt"? Were any leaves at all left? Is the basal rosette left? If yours are annuals, if there is something left to work with you might get regrowth and another flush of blooms.

Do you have a tag still?

Dee