The cranial nerve that has been primarily affected by the viral infection is the facial nerve, otherwise known as the seventh cranial nerve (CN VII). The facial nerve is responsible for controlling facial movement and expression and also carries nerves which affect tasting and production of tears – majority of which the patient has been experiencing difficulties with in this case.
References:
Mayo Foundation for Medical Education and Research. (2022, May 4). Bell’s Palsy. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/bells-palsy/symptoms-causes/syc-20370028
What is the facial nerve?. Otolaryngology - Head & Neck Surgery. (n.d.). https://med.stanford.edu/ohns/OHNS-healthcare/facialnervecenter/about-the-facial-nerve.html#:~:text=The%20facial%20nerve%20is%20the,producing%20tears%20(lacrimal%20gland).