A tongue polyp is medically known as a fibroepithelial polyp. It is 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 papilloma and fibroma. These are all benign conditions.
I would suggest that you visit an ENT Specialist for an assessment. The lump can be removed by a simple surgical excision under local anaesthesia.
Hope this helps and all the best!
