Hooked up spare battery to the wrong terminals now have no power at all lights still work but no dash lights? what could it be is there a fuse that might have blown or something worse?

Under the hood is a fuse box. In this box is going to be a large fuse (between 60 and 100 amps usually) and it may be labeled 'main', 'alt', or 'batt'. This is the fuse that runs from the battery to the main power of the vehicle. When you hook a battery up like that it blows this main fuse. You'll need to replace that and any other fuses it blew out.