Environmental conditions like wind, dry air and too much sun exposure can cause chapped lips, which leave redness in the corners of your mouth. A deficiency in iron or riboflavin can cause lips to chap and corner of mouth to redden. Angular cheilitis is an inflammatory condition that affects the corners of your mouth, leaving them red, cracked, blistered, bleeding or painful. Keep your lips and corners of mouth covered in lip balm containing petrolatum. You can try a multivitamin and a b12 suplement.Since this problem is persisting since a long time it is best to seek the opinion of a dermatologist in a medical college. I do hope it helps.
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