A tongue polyp is medically known as a fibroepithelial polyp. It is a benign condition that usually appears after some trauma to the tongue (e.g. after accidental tongue biting). Most tongue polyps do not cause symptoms. Other tongue lesions that can look like a tongue polyp include a papilloma and fibroma. Fortunately, they are also benign lesions.
I would suggest a visit to an ENT Specialist for an assessment. A tongue polyp can be removed by a simple surgical excision under local anaesthesia.
