The viral infection caused her to be unable to move the muscles on the right side of her face. Hence, the Facial (VII) nerves on her face are affected. Facial (VII) nerves are responsible for muscle contractions for facial expressions. These cranial nerves are also responsible for regulation of saliva and tears secretion. The viral infection to the Facial (VII) nerves also caused the loss of taste and dry mouth.
References
Tortora, G. J., & Derrickson, B. H. (2018). Principles of anatomy and physiology. John Wiley & Sons.