Flies prey on the dog's ears and sometimes bridge of their nose for the tender skin here and the inability of the dog to protect this area. Similarly, the rump area is often a target.
What soothes dogs ears?
Spray a mixture of equal parts apple cider vinegar and distilled water into the ear. Vinegar can fight bacterial and fungal invaders and soothe swelling. The acid may ease any pain that your dog is experiencing. An alternative to vinegar is witch hazel, which itself has anti-inflammatory properties.