u have pitted your button head and maybe piston head the good news is your engine didnt break any parts. easily done like what brag mention, get 1200 grid sand paper and smooth button head gently and polish top part of your piston. if the compression is still there, maybe need to remove 0.1mm shims.

what i've seen locally OS engines are really weak against lean bottom end settings. mostly end up breaking con rod and in 4 out of 5 cases its total loss. and get your conrod replaced.

just my humble opinion