Hi, Welcome to healthcare Magic. This drug has a known side effect of weight gain & edema due to fluid retention. Which may be reversible after discontinuation, if you lead a healthy life style otherwise . It may also effects periods & may even cause absence of periods. This effect is also reversible once you discontinue the drug ( if this medicine is the sole cause of your period irregularity otherwise you need a Gynecologist consultation). I hope you know that females of childbearing age who are sexually active, should employ non-hormonal contraception throughout the course of this treatment. I don t know your exact diagnosis & what type of cyst you have. I hope you have started this medicine on prescription of a qualified Gynecologist & not taking it on advise of a friend as it s use may not be allowed in undiagnosed ovarian masses. Periodic tests of liver function and complete blood count should also be considered during it s use. Hope I have answered your questions properly. Best Regards.