Ringworm under the corners of the mouth, consider the following possibilities: the first possibility, neurodermatitis, this disease mostly occurs in people who are mentally stressed and stressed, need to carry out soothing emotional regulation, to ensure good rest and sleep. In terms of topical medication, you can apply tacrolimus ointment, pimecrolimus ointment, and apply it twice a day. For severe itching, you can take oral levocetirizine hydrochloride oral solution to enhance anti-allergy treatment. For the second possibility, consider ringworm of the face, caused by fungal infection, at which time topical naftifine ketoconazole ointment and luliconazole ointment can be applied as an antifungal treatment. The third possibility is atypical ringworm, which is usually caused by a fungal infection of the face and the application of glucocorticoid ointment, resulting in the aggravation of the rash and the appearance of atypicality. In this case, anti-allergy and antifungal treatment should be intensified, and trimethoprim ointment can be applied. However, this drug has a certain amount of hormones, it is not easy to apply for too long, and the effect can be stopped after 3-5 days of application.