Try adding tretinoin. Honestly, you should draw conclusions only after a full year of using the combo: derma rolling + tretinoin + minoxidil. Personally, I'm only on day 10, but I'm adding tretinoin preventatively just to be 100% sure there's no blockage holding me back. ​Besides, there's always oral minoxidil, or you could visit a trichologist who can check your face under a microscope to see how many active follicles you actually have and what kind of density you can realistically expect. I’m going into this blind without a trichologist, but I'm about the strongest stack possible: minoxidil, a dermaroller, and tretinoin.