If it is not possible to either push out the dent or use a dent puller, you will probably need to hammer it out. If the area behind the dented panel is easily accessible, this will make life a lot easier, but if it is not - be prepared to remove the entire panel from the vehicle!
Bear in mind that the object of beating out a panel is not to achieve a perfectly flat surface like it was originally, this would be almost impossible. The idea is to hammer the panel so that the 'restored' section is actually just below the original level. That way the imperfections of the much reduced dent can then be filled and sanded down to a perfect finish.
If not still on the vehicle, make sure the removed panel is secured firmly. Using a light hammer tap around the edges of the dented section. From time to time reach round to feel how the dent is coming out - remember it must not protrude. Work inwards towards the centre so that the surface is slowly restored to a level that is just below the original.
Try not to be impatient, the dent should be gradually worked back into shape. Using large blows will just stretch the metal even more and make things worse!
Finally fill the last small dent with filler, sand and re-spray.
Unless you are extremely experienced in this type of repair, please seek the advice of a repair center as misshaped panels and bad colour matching can be costly to rectify.
Car bodywork and accident repairs
At Accident Repair Finder we can provide free help for you following a non-fault road accident. We specialise in managing and arranging repairs and car-hire after road traffic accidents.
If you have had an accident that was not your fault, we can provide these services for you absolutely free because we claim all our costs back directly from the at-fault party's insurance company.