2, as for the car paint dropped to see the primer, it is best to go to the repair shop to repair it. Don't be too expensive, just accept it. If it is a small place, it will be 100.

No matter how big the problem is, if there is no perforation, it is best to ask the garage not to weld the car panel. If the sand board is too thin, the temperature during welding will burn the surrounding paint surface and sand board, and it will rust more easily in the future.