You can use any size dermaroller any time you want, even every day but do not use it on the same skin area. Roll each time a different skin area. If you do not push the needles in too much, you can roll the same skin area more frequently than is in our instructions.
Concerning a ten-row dermaroller:
The fewer needles a dermaroller has, the deeper they penetrate and the easier they get into the skin. The reason why fakirs can lay down on a bed of nails is that there are many nails the pressure gets evenly distributed and becomes to small to penetrate the skin.
It takes more time to roll a large area with a five-row roller but the needles penetrate deeper and easier. It is already quite difficult to make even one needle penetrate the skin because the skin is a very tough, protective organ.
Yes, you can use the single needles on your brown spots but not every three days.
Needle them densely every three weeks. If you do not needle deep, then needle every two weeks. If the pigment is in the epidermis, it will be easier to improve. If the pigment is in the dermis (deeper skin layer) it will be very difficult. Pigment-producing cells (melanocytes) normally reside at the bottom of the epidermis only. Sometimes the membrane between the epidermis and the dermis gets damaged and some melanocytes sink deeper and produce melanin in the dermis. It is hard to solve.
Usually, the pigmentation is in the epidermis and a 1.5 mm dermaroller is unnecessarily long. Using a 0.5 mm size is sufficient.
Pigmentation spots very often reappear as soon as they are exposed to the sun.
If you have brown spots you should definitely use the A-Ret gel - it speeds up the turnover of the skin and vit. C serum -it is an antioxidant that will partially prevent further sun damage including the formation of brown spots and it is a mild skin lightener if used long-term.
Related postings:
https://http://forums.owndoc.com/dermarolling-microneedling/Hyperpigmentation-on-dark-(African)-skinv/a>
https://http://forums.owndoc.com/dermarolling-microneedling/Dermarolling-against-hyperpigmentation/a>