Can a Dermaroller Damage Hair?

I am interested in using a dermaroller to enhance topical absorption. How long can the needles be before there is a risk of damaging the follicle and the surrounding vasculature?

We do not use or have experience with a dermaroller. I had one on my desk to play around with, but it never got use on the scalp, so I am the wrong person to ask about this one. I wrote about that years ago. It still looks painful.

In general, anything with a sharp point or a needle that you use on yourself (or others) should be sterile and used with caution. If there are readers out there that use this product, I’d be curious to know what you think about it.