We already do have drugs like that. The most popular is RU58841. Its a topical that competes against DHT to bind to the androgen receptors, what that means is if RU is attached to the androgen receptor then DHT can't harm the follicle. The problem with this is that the drug is fairly weak and its had mixed results at best. One of the drugs I'm using internally ( Cyproterone ) does the same thing but to a greater degree ( plus stops testosterone production, ect. )
For some people there is more to male pattern baldness than simply androgens, which is what seems to be the case for me.. But currently DHT is recognized as the main culprit for male pattern baldness so Anti androgens and DHT blockers are the go to treatments we use.
Dermarolling is used to create microwounds on the surface of the skin. It causes your skin to regenerate and build new, fresh cells which hopefully help grow new hairs. Its also used for better absorption of topicals like minoxidil and RU.