  Assume that $G$ is a graph with edge ideal $I(G)$. For every integer $s\geq
1$, we denote the squarefree part of the $s$-th symbolic power of $I(G)$ by
$I(G)^{\{s\}}$. We determine an upper bound for the regularity of
$I(G)^{\{s\}}$ when $G$ is a chordal graph. If $G$ is a Cameron-Walker graphs,
we compute ${\rm reg}(I(G)^{\{s\}}$ in terms of the induced matching number of
$G$. Moreover, for any graph $G$, we provide sharp upper bounds for ${\rm
reg}(I(G)^{\{2\}})$ and ${\rm reg}(I(G)^{\{3\}})$.
