Really the worst is to have an old piston ring break apart. Does a lot of damage to the cylinder walls. But an old piston, nah. You lose the original concentric grooves on the surface of the piston that helps with distributing an even coat of oil on the piston. And you might have some wear on the piston body that causes an increase in blow-by and a subsequent reduction in compression.
Only reason I suggest looking for an air leak in the inlet path is that I’ve got two pistons that look identical to what you have (no clear indication of detonation, melted on exhaust side).
Look for excessive oil around the seals of your carb boot.
Also, what oil to fuel ratio are you running? What engine is that?