Using white on white fabrics can sometimes trip you up, as to which is the right side, but if it takes you quite a while to figure out which is the right and which is the wrong side, leave it along, as nobody else will know either. Don't get me wrong, I love white on white fabrics and use them a lot in my quilting, but if it isn't immediately noticeable, one side or the other, don't sweat the small stuff.