Why do i get ulcers in my mouh regularly?

Oral Ulcers: Could be infection vs irritation vs allergic to food/medication. It also depends on travel history, sexual history, occupational history. All of these things are important. It could even be that you had recent dental work (?) and you have a nickel allergy that causes these ulcers. Definitely get them checked out. If you don't have them on the date of ur appt, take pictures beforehand.

Behcet's disease: Recurrent canker sores have several causes but behcet's syndrome should be ruled out - especially if your heritage is central or east asian. Behcet's syndrome is an autoinflammatory disease & involves defects in intrinsic immunity. A board-certified immunologist may help. Depending upon where you live that might be an allergist or rheumatologist.

Regular oral ulcers: Common causes of recurrent oral ulcers are canker sores (aphthous stomatitis, cause unknown) and cold sores (oral type 1 herpes simplex infection). But it can be caused or associated with other infectious (vial like typ 2 herpes simplex, fungal and bacterial) and immune-mediated (lupus, crohn's, behcet's) diseases.