A tick from the engine does not always mean you've done damage to it. You could have a stuck lifter or lash adjuster, running some seafoam (or simular additive) thru the engine and in the crank should cure that, some of the kia heads (not sure if the rio falls into this area) have a known history of around the 60K km mark and onwards of the intake valves not seating correctly, causing a ticking sound. the fix for this is to pull the head and hone the seats. It could also be a pin-sized hole or crack in the exhaust manifold or a leaking exhaust gasket. It could also be a failing injector, or one of another half dozen things!
If your timming belt has gone you'd have more issues than a simple tick, why would you assume you have damaged the valves and pistons?