I'm trying to get my table correctly displayed but I don't know why it's not working:

Can someone please help me? Here is the code of the picture:
\documentclass[a4paper,12pt,twoside]{book}
\usepackage[bottom=25mm,top=25mm, left=30mm, right=25mm]{geometry}
\usepackage[utf8x]{inputenc}
\usepackage[spanish, es-tabla, es-noshorthands, es-nosectiondot]{babel}
\usepackage{multirow}% http://ctan.org/pkg/multirow
\usepackage{hhline}% http://ctan.org/pkg/hhline
\begin{document}
\begin{table}[ph]
\centering
\begin{tabular}{|c|c|c|c|}
\hline
\multicolumn{4}{ |c| }{Blah} \\
\hline
\multirow{1}{*}{C1F1} & C2F1 & C3F1 & C4F1\\ \hline
\multirow{2}{*}{C1F2} & C2F2 \\& C2F2 &\multirow{2}{*}{C3F2} & \multirow{2}{*}{C4F2}\\ \hline
\multirow{1}{*}{C1F3} & C2F3 & C3F3 & C4F3 \\ \hline
\multirow{2}{*}{C1F4} & C2F4 \\& C2F4 &\multirow{2}{*}{C3F4} & \multirow{2}{*}{C4F4}\\ \hline
\end{tabular}
\caption{blablabla}
\label{blabla}
\end{table}
\end{document}

\multirow{-2}{*}{C3F2}(note the minus sign), which means the two rows above this row. – Peter Grill May 20 '14 at 20:27\multirowcommand up one cell. – Werner May 20 '14 at 20:30