It takes time, and even at 5 months is early. There are taste buds all around the mouth, and in the back of throat, and may have been where most of the radiation was directed at, if oropharyngeal cancer, and could be reason for the continued difficulty in the back of throat area, and takes time for taste buds, nerves to recover from radiation, and chemo, if given. Saliva and taste go hand in hand, and also helps moisten the food to swallow. Drinking water, lemon water, chewing gum, hard citric candy, even sucking on stone fruits may held with saliva. Milk has enzymes that replicates saliva, coats the mouth. Sugar increase salivation. Adding healthy oil to foods may help with swallowing, plus adding extra calories, and taste. I have an oil mister bottle called misto. Zinc supplement may help with taste buds.