Hello, I went through your query, Multiple factors may cause canker sores(apthus ulcers) , including injury to the mouth, acidic or spicy foods, vitamin deficiencies, hormones, stress, or autoimmune disorders. Canker sores are not the same thing as fever blisters (coldsores). Most canker sores require no treatment and resolve on their own. Eating more of fresh fruits and vegetables, including citrus fruits helps to prevents this happening frequently,, b-complex vitamin supplementation helps. Please consult a general physician for prescription.