From the photograph, I can see a bluish-purple/red area on the inner cheek/throat-side tissue. It is difficult to identify the exact cause from a photograph alone. It could be related to normal blood vessels, local irritation/trauma, or inflammation, but a persistent colour change for almost 2 months with pain should be examined in person.
Your history of tongue biting, mouth breathing and snoring could contribute to repeated irritation. GERD can also contribute to throat irritation, but it would not be safe to assume that GERD is the cause of this visible area.
Next Steps
* Please arrange an examination with an oral medicine specialist or ENT.
* Show them the exact area and mention that it has been present for almost 2 months.
* They may simply monitor it if it looks harmless, or recommend further examination/testing if the appearance is unclear.
* If the area is actually an ulcer, lump, or unexplained red/white patch, persistent lesions generally need proper evaluation rather than continued observation at home.
Health Tips
* Avoid repeatedly touching, scratching or biting the area.
* Try to prevent tongue/cheek biting during sleep and discuss the snoring/mouth-breathing with your doctor or dentist.
* Manage your GERD as advised by your physician.
* Avoid tobacco, areca nut/supari, alcohol-containing mouthwashes and other irritants.
* Don’t panic based on the photograph—a coloured area does not automatically mean something serious.
* However, because this has persisted for ~2 months, I would not wait several more months to have it checked.