Minoxidil has stopped working (I think).

[VictimOfDHT]

I've used Minoxidil for more than 15 years and it's worked really good for me -even better than Fin- in maintaining the hair I have but I think it's becoming much less effective now or maybe non at all as I've been having an accelerated loss of hair over the past year. I'm not sure if the scalp develops some kind of resistance to minoxidil or something but the reason why I think it does is that for many years every time I'd apply Minoxidil I'd get this itch and burn on my scalp but this last year when I apply it I don't get any itch or burn on the scalp however, if a drop runs down my forehead or behind my ear I feel a slight burn or itch. So, it's like the skin that's not used to minoxidil is more sensitive to it.

Now, is there anything I can do to improve the absorption of minox into the scalp? Just started derma rolling but any other suggestions?
I'd appreciate a reply.