Stitch them one at a time. ie.
Break all the bad splines and delete any unused cp's, now fill in the "hole" by continuing the centerline spline first, then stitching the neck spline loop together with the new centerline. You will have to edit the resulting cps location in the "z" axis when done.
Be sure to have your "show bias handles" button checked, as they will quickly show you when a spline is discontinuous or coming out of the cp connection the wrong way.
This will work most of the time. Sometimes (mainly when splines are at a fairly close angle to each other) it's necessary to do this in two steps.
1. Click and add your new spline, if it seems to be coming out of the "wrong" loop, complete just the first new cp and leave it dangling.
2. Now if you try again, the connection should be correct (as the other direction is taken) and you can go ahead and stitch away. Once done just delete the dangling spline.
One more thing, you should get rid of the "5 way" connection at the base of the neck on both sides. Just continue the loop below the upper one all the way around, or deadend it with a hook.
Try to avoid these types of joins, except in places where a small crease will not hurt you.
Phil