Of course, you can take out the stitches and re-quilt those areas, redistributing the fullness on the back evenly. Alternately, since you said they are bad tucks, you can press them down flat and applique the sides down. This would be less noticeable on a solid color instead of a geometric print. Fleece is thick, though, and if you choose to do that you may need to mostly cut the flaps down the crease so you can split them open before appliqueing them down to reduce the thickness. Good luck.