Imperforate hymen is a congenital defect of the lower genital tract and specifically the vagina. The examination of a neonatal can be quite helpful to avoid a multitude of complications in puberty like hematocolpos and tubo-ovarian abscess. We present the case of a 16-year-old who presented to the emergency department with fever (37.9° C), which was progressive the last two days, swollen abdomen, and pain in the lower abdomen. She also had a one-year history of cyclic abdominal pain. The patient had primary amenorrhea, the secondary sexual characteristics were normal for her age (Tanner III), and there was no family history of primary amenorrhea. The physical and ultrasound examination revealed an imperforate and bulging vaginal membrane and a multilocular adnexal mass, respectively. Every doctor should suspect this medical condition when there is a triad of symptoms like cyclic lower abdominal pain, primary amenorrhea, and swollen abdomen. Early diagnosis of an imperforate hymen can prevent serious complications for young patients.