You will need to measure your cylinder.
If you don't know how or have the tools, take it to your nearest Kawi dealer and have them measure it for you.
Clean the inside of the cylinder really good so they can look at it for you and make sure it is still usable.
If I saw detonation like your piston shows I would get a new one.
While you have the top end off you should measure the rod to crank clearance..
And, after all that you need to figure out why you are having a detonation problem.