You did not mention your dog's age. Most common symptoms of facial paralysis are its dropped appearance. One ear lowers down. Lip drops down from effected area. In this conditions dogs drop down food from their mouth. There can be many reasons for this disease but in your dog it is due to its already effected ear. It is deep- seated infection of the ear (otitis media/interna). That means your given antibiotics were not according to its already existing disease which made it even worst. Go to vet and tell him this possibility in detail to get exact diagnoses through X-Rays of the skull to see the deeper part of the ear (middle and inner ear).