Answer: Usually it is not a good idea to prune azaleas after mid summer because you will be removing blooming wood for next spring. It may also encourage additional soft tender new growth that will be more susceptible to winter damage, unfortunately.
At this point, try to make sure it is well watered through the fall up until the ground freezes as being well hydrated can help the plant withstand the cold better. Winter protection would also be a good idea, especially wind protection such as burlap as well as a good layer of organic mulch over the roots but not up against the stems.
Trimming it would encourage additional branching and make it grow denser. I am not sure why you felt the need to prune, but in my experience apart from possibly a light shaping every few years, these plants do not usually require much pruning at all. In any case, the trimming might well result in fewer flowers next spring but shouldn't cause permanent damage. Enjoy your azalea!
Q&A Library Searching Tips