No it won't darken the wood. That's why you need stain if darker wood is desired. It's very easy to repair finish by using the can-not the spray, and take a brush to apply it evenly in area to be repaired. You can use the spray and lightly sand down surrounding area down even with the repaired spots. It LIKELY won't be necessary to repair it however as it's MUCH more durable and protects the wood better than Tru-Oil.