Okay. One relatively common cause of mouth dryness is poorly controlled diabetes, probably related to the frequent urination and mild dehydration that can develop if the blood sugar is high. Closer control of your blood sugars could improve the oral dryness you describe. Talk with your doctor about whether tighter blood sugar control would make sense for you.
Speaking of dehydration, now comes a related question.
Dehydration is a term that means "too little water" and is common among persons with diarrhea, vomiting, fever, those who take diuretics (water pills) or poorly controlled diabetes. Exercise in hot, humid weather is another common cause. Symptoms include thirst, a dizzy feeling when arising, headache and fatigue, and mouth dryness.
Based on this information, do you think you may be dehydrated?