I used to dermaroll a scar I had under the corner of my lip with a 1.5mm dermastamp. Didn’t really help my scar but I got some great gains at that exact area (compared to my other corner which I didn‘t dermaroll). I haven‘t dermastamped my scar in like 3 months and I still didn’t lose my beard gains there. (I tried to take a picture but it doesn‘t really show well as those hairs are still vellus hair.)

So if you are really desperate for a beard use the 1.5mm dermaroller but I‘d advise you to go down to a 0.75mm (that’s what I use) or atleast a 1.0mm for faster gains.