I have been using 2mm derma roller for deep scars on my face. I'm not feeling any improvement but new scars. Is this normal?

I have been using 2mm derma roller for deep scars on my face, with each application I'm using moisturizing cream, Vitamin C+E Serum and Collagen cream, I have done more than 8 session(Weekly) but I'm not feeling any improvement even I'm seeing new box car scar appear on my face.. What could be the reason for that and what is the best solution? Thank a lot.

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