You may have bumped someone or they may have bumped you. Whatever the case, you now have a dent in your car's bumper. You can take the vehicle to a bodyworks garage and pay the mechanics there to remove the dent for you, or you can save some money and attempt to do it yourself using a hair dryer and an air duster. Most people have a hair dryer at home, and you can pick up an inexpensive air duster that's full of carbon dioxide at most grocery, home improvement or office supply stores. For this do-it-yourself fix, you do not have to get underneath the car to fix the dent. If the dent is really deep, you may not get the results you are seeking. The bumper may need to be repainted or it may not come out all the way. If you don't like the results, you can always take your car to an auto shop and pay them to fix what you could not.
Plug the hair dryer into an electrical socket so it is near the bumper you are trying to fix. You may need to use an extension cord if the hair dryer's cord is not long enough.
Turn the hair dryer on and heat the dent in the car's bumper for at least one minute, holding the hair dryer about two inches away from the dent. Move the hair dryer around so it heats the entire dented area.
Spray the dented bumper with an air duster for 10 seconds immediately after spraying it with a blow dryer. Make sure you hold the bottle upside down so the carbon dioxide comes out. A liquid from the air duster will coat the bumper while you are spraying. This is normal.
Wait a few minutes to see if the dent pops out. You may hear a "popping" noise.
Allow the liquid from the air sprayer to dry and then wipe any remaining residue off with a soft cloth. Repeat the process if necessary.