In most cases damage will stop and what fell recently will come back at least partially. Though if you want to make sure or if you have a pretty fast evolving case, there's finasteride and dutasteride. Those "big guns" will ABSOLUTELY ensure that no further damage is done, and maximize regrowth.
But yeah, if your testosterone is appropriately assassinated by spiro (check your blood levels!), chances are that your hair will go back to normal.
It still wasn't really visible to others, but before I started HRT, my hairline had progressively masculinized itself a bit since the beginning of my puberty. It was starting to have a bit of an M shape, with small bays forming on the "corners".
But now, I look at it in the mirror closely, and the bays have filled in, and they're now just areas of thinner, shorter, younger hair. My whole hairline has also advanced a little, which I guess means I wasn't hallucinating my forehead growing higher. My hairline has also become rounder. It was roughly square before, but now it's much rounder. The hair in the "bays" is still pretty light, though, so of course the corners are still a bit visible, but I'm actually hoping to have a completely female-looking hairline eventually.