Microneedling from Reddit (photo)

Once a week to every ten days is the routine for microneedling. You just have to hold the pen against the skin and the instrument will take care of the depth as it cycles. The use of a Dr. Pen microneedling device at a depth of 1.5mm can produce considerable bleeding. You should probably reduce the needle depth to 1mm so that the bleeding will not be so great.  There is another problem I see here, and that is the area you covered is the same area as your original juvenile hairline.  The juvenile hairs in that old hairline are unlikely to come back. The area where you have receded, will more likely come back which reflects the transition to a mature hairline possibly with recession. That is within the area outlined by the blood.  I would like to see a mature hairline drawn on your head and then see you microneedle that area.  Read my article on hairlines that mature: https://newhair.com/wp-content/uploads/2018/11/phenotype-article-published.pdf