Using a needle and thread (not a machine) stitch closed the hole left from turning the quilt. A "blind" stitch is a good choice but a little more complicated than the simple whipstitch shown in the photo. To start sewing, make a knot at the end of the thread (directions here:
http://heatherbailey.typepad.com/photos/my_favorite_knot/index.html ) and lodge the knot into the batting. Pull the needle out through the front of the quilt. Fold in the raw edges of the quilt front and back (you may want to pin) and stitch as shown in photo looping from front to back. Knot off at other end again hiding knot inside the quilt.