Scalp/Dermaroller

Has anyone tried using a scalp roller/dermaroller on their scalp?

I'm doing some readings about it and saw several different brands like this Scientia Scalp Roller, which seems to be the only one with "believable" advertising.

Any thoughts about it?

I tried it for 8 months and no results. BTW-my Dermatologist couldn't believe it's FDA approved!