This looks like a painful mouth ulcer/aphthous ulcer with local swelling. It is usually due to stress, minor trauma (lip bite), acidity, low
B12/iron/folate, or infection. For relief: use warm salt-water rinses 3–4 times daily, avoid spicy/hot foods, maintain hydration, and use a topical oral ulcer gel/paste as advised by a doctor/pharmacist. If pain is severe or eating is difficult
Next Steps
please book a consultation for proper treatment and prescription. Seek urgent dental/medical care if fever, pus, rapidly increasing swelling, trouble swallowing, or ulcers lasting more than 2 weeks occur.