Flat tongue ringworm is correctly referred to as lichen planus, patients can apply glucocorticoids, retinoids, immunosuppressants and other internal drugs and external drugs under the guidance of the doctor. 1.Internal drug treatment: 1) Glucocorticoid: one of the main drugs for the treatment of this disease, it can be used to treat severe cases, vesicular ulcerative mucosal damage or progressive nail destruction or alopecia. 2) Vitamin A-acids: commonly used is Avitamin A. This type of drug should not be taken by pregnant women or women who are about to become pregnant. 3) Immunosuppressants: commonly used for those who are insensitive or contraindicated to glucocorticoid therapy, or stubborn and intractable lichen planus. 2. Topical drug therapy: 1) glucocorticoid: small area of damage can be used alone. Such as hydrocortisone, dexamethasone and so on. 2) Vitamin A acids: topical avitamin A ointment, isotretinoin cream or ointment, etc. If topical glucocorticoids are used at the same time, the efficacy is better. 3) immunosuppressant: such as 0.1% tacrolimus ointment, or cyclosporine oral gargle. The individual differences in patients with lichen planus are large, need to be under the guidance of the doctor in combination with the personal situation of the use of relevant drugs for treatment.