I'm sorry to hear that your mouth ulcer has lasted this long despite treatment. Mouth ulcers that persist beyond two weeks warrant careful evaluation because they may indicate an underlying issue that needs specific management.

Here are some important steps you should take:

• Consult an Oral Medicine Specialist or Dentist promptly for a thorough examination. Persistent ulcers can sometimes be caused by infections, nutritional deficiencies, immune conditions, or rarely, more serious issues.
• Avoid irritants such as spicy, acidic, or rough-textured foods that may worsen the ulcer.
• Maintain good oral hygiene using a soft toothbrush and mild mouth rinses.
• Since you have already tried antifungal (Candid) and antibiotic (Novamox 500) treatments without improvement, further investigation like biopsy or blood tests might be necessary to identify the cause.
• Stay hydrated and consider a balanced diet rich in vitamins, especially B-complex, iron, and folate, which support healing.

Please do not delay seeing a specialist to get an accurate diagnosis and appropriate treatment. If you experience severe pain, difficulty swallowing, or any other concerning symptoms, seek medical attention immediately.To narrow down potential causes, we will need some more information.I understand you've been dealing with a mouth ulcer for 20 days despite trying Candid and Novamox 500. To better understand your situation, could you please share your age and gender?