What can I do for my behcet's syndrome without going to a doctor?

Little. This autoimmune disease affecting the mouth, GI tract, genitalia and eyes, can only be treated with serious pharmacological intervention. Home remedies may provide a little symptomatic relief but do not affect the basic disease. Only your doctor can provide the type of relief that is helpful in the long run for this serious, debilitating and chronic disease.
You may suffer more. While behcet's disease is rare, and there is no cure, there is benefit from currently available treatment to lessen pain and to prevent some of the irreversible consequences of untreated flares of this disease. You should be under the care of a rheumatologist for optimum treatment and outcomes.