Regards This problem could be one of the following: 1. Viral Stomatitis (Most common) - This infection is recurrent (almost 6-7 months). Includes periods in which crusts appear on the lip as well. Treatment: Any gel for Oral ulcers. Specifically : Acyclovir 500 mg - Advised not to self medicate. 2. Apthous ulcers (Quite common) - Ulcers appear in mouth almost every 2-3 months 1 or 2 small or medium in size and cause significant pain. Remain for 6-7 days. Treatment: Any gel for Oral ulcers. Specifically: Becasoule capsules twice daily for 1 week. 3. Erythema Multiforme (Rare) - A reaction to some medications and foods. Huge oral ulcers with crustations. Treatment: Any gel for Oral ulcers 4. Lichen Planus (Uncommon) - Autoimmune oral and skin disease. Requires consultation. 5. Pemphigus (Rare) - Autoimmune oral mucosa disease. Requires consultation.