I'm shedding or have I damaged my scalp/hair follicles?

Im currently on Finasteride(4m) and Minoxidil(2m). 2m ago I tried a dermaroller 1,5mm once. I used it carefully and without any noticeable bleeding, my scalp got little sore for a day, the dermaroller was of poor quality. My hair have got thinner since starting medication, so I can't judge if my hair is thinner because of shedding or if the dermaroller is the cause and that is really stressing me out. Is it likely that the dermaroller is the cause of this hairloss? If yes, is it permanent?