A burning sensation on the tongue can happen due to common causes like vitamin deficiencies (especially B12 or iron), oral infections such as Oral Thrush, acidity, dehydration, spicy foods, or even stress. For relief, ensure she drinks plenty of water, avoids very spicy or hot foods, and maintains good oral hygiene (gentle brushing of teeth and tongue). You can also consider giving a balanced diet rich in vitamins, and a doctor may advise supplements if needed. If the problem lasts more than 1-2 weeks or worsens, it is best to get her checked to identify and treat the exact cause properly.