Please advise

Hi mummies i have a daughter age 12 years old last month and this month my girl menses was not fully flow but ended till 17 days and more. Her menses blood only flow the 1st and 2nd day normal colour blood. But next few days will be brownish but a lil bit only. I have already bring her to see pd at poly. But they only give her a hormon pills to stop her period as her menses has not stop. They ask me to go kkh coz they don't hv a specialist at the poly. Im a little bit worried about her menses. And I'm afraid if i bring her to kkh they will do something not good at her vagina as she is still virgin 😔 just because to check what's happening. #advicepls