Hi…. Welcome to HEALTHCARE MAGIC... I have gone through your query and can understand your concerns... Sinusitis, is one of a cause of swollen roof of mouth, typically caused by infection, allergies or exposure to chemicals and particulates in the air. This can be caused by sinus pressure pushing on the mouth or bacteria irritating the flesh inside the mouth. Infected tooth on the top of mouth, can put pressure on the palate behind the gum line. A tooth abscess can cause ulcers or an infection to develop which may spread to the roof of the mouth if it is left unchecked. I will advise you to:- •Consume foods that are high in vitamins B and C can help infected sores in the mouth heal more quickly. •Salt water: It will help with pain and sterilize the mouth in case of infection. •Tea tree oil is anti-bacterial, anti-inflammatory, and can help soothe pain. Make a mouthwash by mixing 10 drops with ½ cup water, swish around and spit after 30 seconds. You may want to rinse with water after. •Go for a dental checkup. •You can treat sinusitis with over-the-counter remedies that include Tylenol (for pain), mucolytic and decongestants. •Treating a sinus infection early will help prevent secondary bacterial infections, which require antibiotic treatment. Hope this answers your question. If you have any additional questions then please do not hesitate in writing to us. I will be happy to answer your question. Wish you good health. Thanks & Regards, Dr.Shiwani