Hello, Your dentist has advised you to see a specialist. A biopsy will be taken if the tissue appears suspicious and a pathological study is necessary. Keep watching and monitoring any changes to provide details to your oral surgeon. The greatest concern is to rule out a malignant melanoma which can have a black-blue pigment. Other possibilities include an amalgam tattoo with a blue-grey appearance, a growth of blood vessels or hemangioma appearing dark blue, a bruise from trauma or a lesion with extra melanin. Some viruses can cause a discoloration and is a possibility since you mention a recent illness concerning the ear, nose and throat area. Karposi s sarcoma is a cancer seen on the roof of themouth. It has a purple appearance, often with swelling, and is an agressive vascular cancer seen in immune compromised patients. I recommend that you follow the advice of your dentist and make an appointment with the specialist. Continue to practice good oral hygiene. Avoid irritants to the oral cavity. Thank you for your inquiry. I am glad to answer additional questions if you provide more details.