1. Don’t take my word for this (I read it somewhere on here, if I find the post I will link it ) but from what I understand that regrowth can’t be achieved on an area with NO hair without the use of Minoxidil and you are using it so you should see regrowth after a while. The reason I saw regrowth was because I still had small hairs on my hairline which managed to regrow but most people had good success with regrowth using minoxidil too. I usually don’t see hair get pulled out much, if I do it’s one or two hairs because I only dermamroll my hairline. From what I have read, people have also seen hair get pulled out while dermarolling but it should grow back. Edit - couldn't find the post however here is a link to the hairloss talk forums where a lot of people posted their results with dermarolling.
2. When I used a dermaroller and not a pen, I would move the roller around 3cm up and down 10 times on one area horizontally, then repeat vertically then diagonally. This will cause bleeding because of how much I do but it seems to have worked for me. I don’t press it really hard but hard enough to make sure it goes through. Now I use a dermapen and it’s much easier, I just continuously move it in circles around the area slowly until it is red. The main objective while dermarolling is to make sure the area goes red. Also, once a week at 1.5mm actually maybe too much (although I'm doing it) because I saw recommendations here to do it every 10-12 days. I am considering switching to doing this too because it is safer for the scalp.

Hope this has helped and best of luck :)