Left my 4S in my friends car today when I was at the beach, for probably 2 hours. I did have it powered off and covered from direct sunlight. When I got back into the car, it was pretty warm. I cooled it off using the AC and didn't power it on until it was fully cooled off. Ive done this a few times before (I don't like taking my phone by sand). Do you think this causes any damage?