I had my oil changed in my 2012 Altima at a dealership and then drove 300 miles when the oil light came on. I pulled over, looked under the hood and found oil cap missing. There was oil everywhere: under the hood, down the side of the car and a puddle on the ground and it was smoking. I immediately had a mechanic check the oil level and he had to put in 4.5 qts. What kind of potential damage could there be?