Microneedling works but it's not amazing. The longer the needle you use (1.5mm or so), the better your results will be. The idea of microneedling is that the needles penetrate into the deeper layers of your skin, leading to induction therapy or the production of collagen. The new collagen is then supposed to fill in any scars you may have, or fix any fine lines and wrinkles you have. I'm only in my mid twenties, so I'm not using microneedling for fine lines but I am using it to help fix some acne scars that I have. And I have had some mild success with microneedling. When I use my roller every night, my scars are invisible the next day, but I equate this more to swelling than new collagen being produced. Because if I miss a day of microneedling, my scars start to slowly return.
After using my roller for more than a year, I would say my skin has had a mild improvement overall, but my scars still remain. On the plus side, when I use my dermaroller at night, there is zero downtime. When I wake up, my skin is not red at all and looks perfectly normal.
A few months ago, I decided to couple my dermarolling with frequent mild chemical peels at my dermatologist's office. The combination of the two treatments has improved my skin's appearance, but again, I still have visible acne scarring. I think I will have to try more aggressive treatments to get rid of my acne scars but those treatments will require much more downtime and I don't want to take a few weeks off from a job that I just started not too long ago.