It’s probably too soon to see any signs of life yet, but you could dig it up and see what’s going on there, then re-plant it if the tuber still looks viable; i.e. solid, not turned to mush.
I treat Dahlias as annuals up here in Zone 4/5, but once in a great while, if we have a big snow cover (insulation) before we get the really cold temps, I’ll have a survivor or two. Same has happened with Gladiolus tubers.
I’ll be potting up new Dahlia tubers soon, for transplanting in the garden, later.
Thanks for the inspiration; I’m going to go look for good articles on Dahlia growing to share. ;)
Check Cultivariable. They’ve been working on developing dahlias with tasty tubers, and they have lots of how-tos on their site.