A 40-year-old male patient complains of having experienced seasonal pain (in spring and summer), and a burning sensation in the lips for 3 years. Examination reveals edema and hyperemia of the vermilion border of the lower lip, numerous erosions sized 2-3 mm, crusts and cracks in the mouth corners. Palpation causes moderate pain, regional lymph nodes are not enlarged, the perioral skin is not changed. What is most likely provisional diagnosis?