when I have a seam come apart.. I use the ladder stitch to repair it. >You take a stitch on the right side and then go straight over to the left side and take another stitch and then that will draw the pieces together ,keep it up as far as you need... you may have to use your ripper and take out a few stitches to line up the new seam. . it will look good.as new if you do it easy and take your time, I have to do it every once in awhile. cmaras
PS> some call it the H STITCH.