Derma Roller caused hair shedding and scar on my scalp

I g ot a buzz hair cut in july 15 july 2024 then i used a 0.5 mm derma roler Like in eery 3 days for 15 days then I had skin shedding on A very small place on scalp. The in August I got A used Derma roller 1.5mm i started using that for next month . After a month. i Realised that my skin become darker and There was no hair on some hairline where They used To be and A little Scar on right side And very thin hair where I had Dence hair. Now Im so sad and feel low . Why i did this with me.Help