A 38-year-old female complains of experiencing pain in her lower lip for half a year, difficult eating and talking. The patient sought medical help at place of residence, but the administered treatment was ineffective. Examination of the lower lip revealed a deep fissure in the centre which affected the vermilion border and partly the mucous membrane of lips. The fissure was covered with a brown crust, after its removal the fissure started bleeding. The fissure edges are hyperkeratinized, infiltrated. Select the optimal treatment tactics: