A patient comes to u with an ill defined, irregularly shaped gingival erosions which are painful and are of short duration, a few months later skin lesions were also noticed, on histopathological examination Tzanck cells were found, probable diagnosis is:
Oral manifestations:

Oral lesions common and precede skin lesions by months
Intact bullae are rare; patients usually present with ill-defined, irregularly shaped, gingival, buccal, palatal erosions, which are painful and slow to heal
Erosions extend peripherally with shedding of the epithelium.
Lichen planus.
Pemphigus Vulgaris.
Angioneurotic oedema.
Behcet syndrome.