Hi. The feeling of dry mouth and cotton in side mouth is due to a form of Stomatitis wherein the salivary glands lining the buccal mucosa do not secrete sufficient mucus / saliva to keep the mouth wet. A course of an antibiotic, metronidazole and oral steroids may solve your problems. Stop smoking, chewing tobacco or chewing gums or such habits if you have. take plenty of oral fluids. use less of toothpaste, avoid too hot and too cold foods and beverages to avoid further trauma. This will help you to come out of the present problem. If you have any other medical problems like diabetes or some syndrome, get an opinion of your Physician. Do not take antihistamine as it causes more dryness.