I'm sorry to hear that your mouth ulcers are causing you so much pain and haven't improved after four days despite taking the vitamin A tablet. Mouth ulcers can be quite uncomfortable and sometimes need more targeted treatment beyond vitamins.

• Since the ulcers are widespread and painful without improvement, it’s important to see a specialist such as a dentist or an oral medicine doctor for a thorough evaluation.
• They may recommend topical treatments like corticosteroid gels or antiseptic mouthwashes to reduce pain and inflammation.
• If ulcers persist beyond two weeks or worsen, further investigation might be needed to rule out infections or other underlying conditions.

If your pain becomes severe, you develop fever, or have difficulty eating or drinking, seek urgent medical care promptly. Otherwise, please follow up with your doctor or an oral specialist soon for a tailored treatment plan.To narrow down potential causes, we will need some more information.Please tell me your age and gender. I understand you're experiencing painful mouth ulcers that haven't improved with the prescribed medication.