That's not bee balm, that is blue mistflower (Conoclinium coelestinum) I believe.
You may have divided the Monarda (bee balm) but Conoclinium coelestinum can reseed from the wild, or seeds blowing in from your neighbors.
It obviously overgrew and possibly choked out the bee balm.
You need to divided the bee balm again and plant it next to the blue mistflower.
Or yank the blue mistflower and plant another division of bee balm its place.