I would turn the motor manually to feel if it turns ok and see if that piston still goes all the way to the top. If it does, chances are the rod is fine.

But, at a minimum I would drop the oil pan and have a look from the bottom. And, while the pan is off, that front cover could use a rebuilding!

 

This.

Clean that cylinder and look for cracks.

Swap, lap the valve or buy a head at the upullit. Put it back together, have fun. By the looks that was minor.