The amount of impact absorbed by the bumper will determine whether the bumper is repairable. Some bumpers will collapse, and other bumpers will break. Fortunately, these two types of bumper bruises can be repaired in almost any case, unless the damage is severe. If the bumper has a lot of cracks or is missing a lot of material, it is best to replace the bumper itself.
To fix the dented bumper
Step 1: Lift the vehicle and firmly support it with a Jack. To secure the Jack Stand, make sure that the Jack Stand is on a firm surface and use the Jack to lower the clamping weld or inner frame of the vehicle to the Jack Stand. You can find more information about fixing the Jack Bracket here
Step 2: Remove the Splash Guard. If applicable, remove the splash shield or mudguard below the vehicle to contact the rear affected area of the bumper. The splash shield will be secured by plastic clamps or metal bolts.
Step 3: preheat the damaged area. Use A hot air gun or hair dryer to heat the damaged area evenly. Use the hot air gun until the bumper is flexible. It takes about five minutes to heat the bumper to a temperature that makes it flexible.
Step 4: Roll out the bumper. When heating the bumper or after heating the bumper, use the pry bar to push the bumper from inside to outside. When you apply pressure with a crowbar, you should note that the collapsed portion begins to roll out. If the bumper is still not very flexible, heat the affected area until it becomes flexible.