Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have pain on lower lip and gingival connecting line which is known as frenum . Well there can be many reasons for the symptoms you mention in query occur due to various reasons like traumatic injury due to any hard thing like tooth brush , it can be chemical or heat burn due certain food and due to gingival recession . Sometimes pain occur due tohigh or low frenal attachment also . I would suggest you to maintain proper oral hygiene , do warm saline rinses , avoid hot and spicy food and apply orabase gel for pain . Consult dentist for proper examination . Doctor will examine physically . Doctor may prescribe steroid gel , anti biotics , perform oral prophylaxis and guide you with brushing technique . Doctor may also refer you to oral surgeon for correction of position of frenulum . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari