Crochetrhu,

Welcome!  So glad you found us! We do have users, though it tends to be quiet here, and I monitor this board daily.

First, I think your piece looks absolutely GORGEOUS!  You should be proud of the work you've done! 

I looked and looked, and finally think maybe I see what you're talking about. Is it the white showing through in that small area toward the bottom (on the sort of left bottom in your pic)? 

If so, there can be several causes. The first thing that comes to mind is tension. Of course we all try to keep our tension even, but have you seen those imperfect humans?  Lol, I know my tension can be all over the place from one minute and one row to the next. Or within the same row. It's next to impossible to keep it perfectly even.

For that, you could frog alllll the way back (unless you went top to bottom), or here's another solution: correct it in blocking. When you're all done, this gives you a way to make your stitches look so much better, without having to frog at all! (This is my favorite method, by far.)

Another thing is it could be your carries of colors. With black and white, it's extra difficult, because there's so much contrast, white on black will look especially prominent.

Are you twisting or catching the yarn as you go, or leaving them loose? Or do you use your yarns from bobbins?

What's showing through could be your yarn carries. I'd definitely recommend blocking to see if that makes a difference with them.

Overall, though... EXCELLENT job!