Though there can be multiple reasons for mouth ulcers but considering the change of weather at present, it could be out of body heat. It's advisable to drink as much of water as you can, preferably coconut water as it balances body heat, take ample of fibres and fruits. If it further persists, visit a doctor.

Hi..., Mouth sores generally don't last longer than two weeks, even without treatment. If a cause can be identified, your doctor may be able to treat it. If a cause cannot be identified, the focus of treatment shifts to symptom relief.... Drink more water.Rinse with salt water.Practice proper dental care. Apply a topical anesthetic cream....Consult Physician if symptoms persists...