If your dad has a mark below his tongue and there is no discomfort or pain associated with it, it's possible that it could be a benign condition or a minor injury that he may not be aware of. However, it's important to note that without a visual examination and medical history, it's difficult to determine the exact cause of the mark. Some possible explanations could include: Trauma or injury: It's possible that your dad accidentally bit or injured the area, causing a mark or abrasion. This could happen while eating or during normal daily activities. Benign condition: There are various harmless conditions that can manifest as marks or discoloration in the mouth. These could include harmless pigmentation, a benign growth, or a normal variation in the oral mucosa. Other causes: While your dad has quit tobacco for several years, it's still worth considering that the mark could be related to his previous tobacco use. However, without a proper examination, it is difficult to definitively attribute the mark to past tobacco use. Since the mark is painless and your dad does not recall any specific incident or discomfort, it may not be an urgent concern. However, it would still be a good idea for your dad to have it evaluated by a healthcare professional, such as a dentist or an oral specialist. They can examine the mark, review his medical history, and provide a proper diagnosis and appropriate treatment, if necessary. Encourage your dad to make an appointment with a healthcare professional to have the mark assessed. They will be able to provide accurate information and guidance based on a direct examination of the area in question.

Poor oral hygiene. Go for scaling and polishing and dental check up. Only after examination one can tell what to do. In meantime apply kenakort ointment

Hello This is look like bite injury.for proper evaluation consult oral maxillofacial surgeon

Has he got any silver fillings done in his mouth and if yes, then in which tooth? If there are silver fillings, it may be an amalgam tattoo. It can also be a nevus or some pigmented (melanocytic) lesion. It needs to be examined. In most cases, it is harmless and can be left untreated esp in those cases where the diagnosis is confirmed and it is not interfering with function or esthetics. However in some cases, a biopsy may be performed to confirm the diagnosis.

visit any oral medicine or oral pathology dentist

Hi. That could be due to irritation ,more like a blood clot,as I can see he has sharp tooth edges.

Visit an oral medicine expert for proper examination.