I'd solder your connector, if you were nearby.
If you have a local facebook group, it could be worth asking for help there.
If there's a little slack in the ribbon cable, could cut it either side of hole, then reconnect using ribbon crimp IDC (insulation displacement connectors). First, just check that the cable is standard ribbon cable pitch, of
0.05 inch (or 0.4" across the eight wires).
The most readily available connector type (available in both plug and socket) are 'D type'. You'd want one 9 way D type ribbon IDC plug male, and one 9 way D type ribbon IDC socket female. Maybe £7 for both on tBay.
Theres a special tool for putting them on, but a small vice works fine. Squeeze, once the cable is in, and square on. Just be carefull, with cable being 8 way, and the connectors 9 way, that cable is at matching end on both connectors.
D connectors have metal bodies. So after repair they'd need insulating to make sure they can't short anything else out.
There looks to be just two conductors damaged, 3rd the temperature sensor and 4th the pump. If pump control is still working, wire 4 must just be holding on.
So another way would be to separate the damaged wire(s), by slicing between with a sharp knife, to give around 4cm of each damaged wire free, to either side, then strip 6mm of insulation from the ends (using
Adjustable manual wire stripper). Use an in line lever connector to rejoin:
3 POLE IN LINE SPRING LEVER CONNECTOR (you'd only be using 2 of the 3 ways). Lift lever, put wire right in, close lever. If wire doesn't pull out, it's connected.
Parts of the power board, or controller board circuits, may have been damaged from short circuit via screw, but repair's still worth trying.