I'm going through a pretty rough one right now, and for some reason it's affecting my sides a lot more which is not good. I do think it'll grow back, but this is looking quite bad right now I've been on propecia about 4 years, all the sheds have come back but this looks like actual receding rather than a shed? ..i need to fix up my temples and sides with some regrowth pronto!!
Mostly in my experience though, any shedded hair has grown back within 2 weeks to full strength and usually better than before.
But each time it happens , I'm never sure...is this the end?! lol