Cracked and flakey toenail, won't grow?

Hi guys, I've had this problem for a while and I am finally sick of dealing with this toenail and want help. I have always worn toenail polish, so my toenails aren't in the best of shape. Some of them are cracked, but they all grow. I have this one toenail (second toe in) that won't grow. It is cracked side to side in multiple areas, and it doesn't grow straight forward, almost inward. It's not ingrown and there is no pain, it is just bizarre and ugly. When I attempt to trim it, it merely peels off layers and reveals bright white, flakey layers beneath it. I am unsure what to do because I am unsure what is going on. If someone could give me some suggestions, that would be great. Thank you!