Modeling Knight- delete spline w/o affecting surface?

At about 2/3 way down tutorial "Refine the mane line" I drew the mane
line, then completed the next step "Mirror the spline arrangement,"
then closed the file. I restarted the tutorial the next day and realized I need
to tweak the mane line before continuing so I deleted the mirror action (so it
was back to half) and deleted the mane spline so I could redraw it but now when
I go to the "surface" command the whole portion near the mane is
deleted though it looks fine in wireframe view. How do I get back to to the
image (#7) just before the "Refine the mane line" as a surface because
the wireframe looks the same except that the surface has deleted chunks missing.
Do I