Mine are jacked, too, and I don't know why. I also don't wear tight styles or braids or use any chemicals. I am going back to using MT on my edges. I'm doing it every other night and rinsing it off in the morning. Then I'm putting on the Qhemet Olive and Honey Hydrating Balm. If I need to smooth the hairline a bit, this helps. It also has a little sulfur in it, so I'm hoping that helps, too.
It's funny, because one school of thought is that you should manipulate the hair that's breaking the least. Then another school of thought is that you should keep it cornrowed. OP, why cornrow the hair every night? Why not just cornrow it and leave it until the next washing/styling time? I'd like to be in on the challenge, but I suck at cornrows and even if I didn't I don't think I'd be cornrowing every night. However for the next time I wash and style my hair (I do it weekly), I think I'm going to do cornrows with beads so that it looks kinda like a hair headband and then I'm going to style the rest of the hair as usual.