one of my large toenails has a deep ridge vertically down it, and it’s really obvious even when I put nail polish on, almost like a crack. I almost need some kind of filler to use before putting on colour. I’ve never had gel nails etc. Any advice on how I can best cover up this deep groove? I’m assuming there’s not much I can do to actually get rid of the groove itself, seems like it might be an age thing.