The Beebalm has a mild case of Powdery Mildew, a very common summer fungal disease. While unsightly, it rarely impacts the health of the plant unless infection is severe (this is not) and recurring year after year. Since this plant is valuable to pollinators, and because the infection is minor, we do not recommend fungicide use.
https://extension.umd.edu/hgic/topics/powdery-mildew-annuals-bulbs-groundcover-perennials-and-vines

The spent flowers are unrelated to the disease and can be trimmed off - this may encourage a small amount of re-bloom, but Beebalm does not re-bloom all season like some other perennials. Trim just above a node (the joint where the leaves emerge) and new growth points should form if they aren't already present (we can see a couple already growing). Otherwise, leave the spent flowers in case they develop seeds that birds can feed on in the autumn or winter.

Miri

Thank you for this!! 

You're welcome!