A tool and method employing sand jetting to perforate a wellbore casing at various locations using sandjetting, and to further flush the wellbore in the region of the tool, and to further frac the formation, all without having to remove the tool from the wellbore. An uphole and downhole packer is provided, uphole of which a sand jet port is provided for jetting a fluid stream containing sand. Locking jaw members and a ‘j’ slot subassembly, downhole of both the jet port and frac port, are together used to set and unset the tool in the wellbore for the fracking operation. A slidable sleeve is utilized to open and close the jet port, and a piston member is further provided to set the upper packer member. A bypass port, selectively openable and closeable, is provided to assist in moving the tool uphole during the perforating and fracking process.