[FWB]

as the cam was being destroyed, particulates of cam material were dropping off bouncing off the crank throws and being thrown onto the piston skirts, scoring the cylinder walls. The smaller particulates have found their way into the oil pump scoring that, also being delivered into the rod and main bearings.
disassemble the engine send the block to be cleaned, replace bearings rings, oil pump, you may need to hone the cylinders, and depending upon how much has to be honed you may or may not need new pistons.

i've been to this show before, it's never a good time. You must run performance oils, not the stuff you get at the auto parts store.
joe gibbs or Penn grade 1 only, in the UK i don't know if these are readily available, but thats my recomendation.

here's a link to my joyous rebuild.......
How a wiped roller lifter is a good thing..maybe