Likely the back won't be seen in the show so can you just accept the way you've done it and go on?
Have you hand basted (or pin basted) the quilt before you started to tie it? If you have, then using a hoop on your lap -- where you can turn the hoop to see how well you've drawn the needle to the back side -- might help.
And as always, practice makes perfect.
Good luck with your entry!
Jan in VA