Burning throat and back of nose, lips always feel dry. could it be allergies?

Possible dry mouth: You may have dry mouth. To promote saliva production you can suck on sugarless candy, drink plenty of water, use a room vaporizer, breath through your nose and not your mouth. Hope this helped :].

Dehydrated: Those symptoms would be considered atypical for allergic rhinitis. Taking antihistamines will likely worsen those symptoms as they have a drying effect. You may consider hydrating more and avoid drying agents like caffeinated beverages and alcohol for a time to see if this improves.