What Causes Blurred Vision And Headaches Post Ventriculoperitoneal Shunting In Brain?

My sister had a vp shunt placed in her brain on Oct. 17, 2014 due to her optical nerves being swollen, declining vision, bad headaches, blurred vision, etc. Before surgery, she was on medications that didn't help. Since the surgery her head hurts worse now then it did before the surgery, her vision is still declining, blurred vision, funny sensations running through her body, etc. The doctor who did her surgery says she's fine because her optical nerves are no longer swollen but her head NEVER stops hurting. What could possibly be going on, is it life threatening and should we get a second opinion?? PLEASE HELP!!!