It depends on the size, location and quantity of the dents.
I have seen people loosen the factory hood, deck lid and roof
cross members to get the PDR tools behind the dent to massage them out. This can actually compromise the structural safety of the vehicle. PDR can also leave small cracks in the paint that can lead to corrosion down the road.
There are several good paintless dent repair (PDR) kits out there, but they are not cheap. Some use glue and pull the dents from the top side.
Torch and file is still popular on the top panels of vehicles. But that then requires primer, base and clear coat after. Hoods and deck lids are usually replaced if they are peppered with a lot of dents, as it's the cost effective way to repair.
There are several good PDR folks out there that are able to quickly fix hail damage. Paintless dent repair takes a while to master. If you do not know what you are doing, or do not have enough practice, you can end up doing more harm then good to the vehicle's appearance.
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