For Over A Week My Mouth Feels Swollen To Include

For over a week my mouth feels swollen to include my lips that are dry, eating burns the inside and food gets stuck between my inner cheek and gums. I have allergies an my sinuses give me headaches if I do not take some form of decongestant. I recently saw the MD and was told to take benadryl., however the mouth symptoms persist. Do you have any suggestions?