Hello dear, Understand your concern. Pap smear does not cause brown stringy vaginal discharge. Bownish to pink discharge after post unprotected sex is pretty common problem in girls. It is normal if not associated with foul smell, itching and abdominal cramp. Pink brownish discharge is due to 1. VAGINAL WALL TRAUMA: it contain atrophied endothelial lining of vagina. so little blood due to trauma mix with cervical mucus form it pinkish colour It indicate disturbance in blood vessels integrity Sexual intercourse precipitate microfissure and frets in vessels lead to bleeding. It can be prevented by using lubrication during intercourse. But if it is associated with pain indicate urethral dysfunction 2.Precancerous condition in cervix: Atrophied cervix get easily damage due to trauma and produce pinkish blood due to mixed with cervical mucus 3. Endo metrial dysplasia 4. Cervical polyp So it might be a trauma to vaginal wall without pain and foul smelling. But if it will not respond you should consult with gynecologist to exclude precancerous condition and infection(STD: bacterial vaginosis an chlymadia) Do the following test: 1. Gram stain and Culture from discharge 2. PCR and nucleic acid amplification test 3. Pelvic examination 4. Usg You should maintain hygiene and keep vaginal area dry. wash by using warm water with added salt. Wear loose cotton underwear. Hope this may help you Wish you good health Best regards Dr. Sagar