I was replacing my head gasket, and i saw this. What do I do now? Can this be repaired? If I have to replace the block, how would I do that? How does this even happen?

I have a 2004 Land Rover Discovery (V8 gasoline). It is misfiring and the head gasket is blown. All the mechanics in my area refuse to fix it, so I guess I will have to do it myself. I have no experience in replacing head gaskets or taking apart engines. It has had a head gasket replacement in...