How can minors handle cyber harassment without involving their parents?

I’m a minor who pretended to be a girl's boyfriend to protect her from her threatening ex. I acted immaturely by pretending I was using her to gather information. The ex admitted to having her photos and even asked me for private content—which I do not have. The girl knows I was pretending. She is from Dhubri, I’m from Kokrajhar, and the ex is from Guwahati. Her brother and sister-in-law, who also live in Guwahati, are aware of the situation. We both have upcoming exams—hers next month and mine are the 12th board exams. We want to resolve this issue privately, without involving our parents. What should we do next?