Looks like it should be re machined. has had some thing go through it ring or washer and looks like it has been run lean or on shitty fuel looks like a lot of detonation.
what would happen if i didnt remachine it ?
iceracer is right, but it should work without problem.
It may detonate some but the reality is most of them do until they are corrected, some run for years some blow through head gaskets and cause other issues. be sure there are no pointed peaks on the squish band, smooth them out with a little fine sand paper. you can run the gasket surface on a piece of glass and 220 grit sand paper to get all the gasket material off and see if has a low spot.
I've watched my grandpa sand down tractor parts the way ice racer just described. Lol