Q.Crepe myrtle blossoms
This spring I was pruning my lilac & pruned the dead shells of the blossoms from last year on my crepe myrtle. Lo & behold I had not one new growth blossom this summer from the crepe myrtle!!! What happened & will they ever grow back?
Crepe myrtle blooms on new growth, so you probably accidentally removed the buds that were going to produce the new growth and flowers this year. Avoid pruning too late in spring, and your plant will go back to normal next year.
Here's more about how to prune crepe myrtle:
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/pruning-crepe-myrtle-trees.htm
http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1009.html