Q: Oil spilled all over the bottom of the car and in the hood area. What damages to certain parts could occur?

Oil will not damage painted or finished surfaces or any metal surfaces such as that of the exhaust system. If left in contact for a long time, engine oil will contaminate, degrade, and damage the rubber components on the motor mounts. If oil has contacted the serpentine belt to any significant extent, such contamination will be difficult to remove and the belt might need to be replaced. Most other under hood parts are relatively resistant to degradation by ordinary engine oils. The principal remaining concerns are the fact that oil attracts and holds dirt and oil can possibly infiltrate wiring harnesses and electrical terminal plugs. The oil change facility is obviously obligated to restore your car to the exact condition it was in before the mistake was made. In the future, if you desire, you can have the engine oil changed, and other services performed, right at your location by a mobile mechanic. For oil changes, request service at this link. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.