Molded body parts like bumper covers can sometimes have "dents" removed by warming them up with a heat gun, hair dryer, or by pouring hot water over them. If using a heat gun stick to the low setting and go slow taking care not to "burn" the paint. I would start with hot water, then move on to the hair dryer and finally the heat gun if not getting the result you want. A molded part wants to return to it's original shape when heat is applied. Watch some videos on youtube and don't be afraid to take your time and multiple applications of hot water. Then touch up with a paint tube. But if you are looking for a "perfect" result then a body shop is the only option. Pricing will vary by market, but expect $500-800 and most shops will insist on painting the entire cover. If you can find a local provider that primarily services dealerships with "spot" touch up you may be able to get that done for around half of a full repaint. If there is a bumper protector or other trim add-on that covers it that would be a great option if desired.
Depending on your desire for a "perfect" repair you can get more aggressive with the DIY options. Many times I have approached something like this with the mentality that if my DIY screws it up I wanted a particular result badly enough that if it failed I was willing to come out of pocket for a professional result, but if not I would approach it more cautiously to avoid making it bad enough I couldn't live with it as is.
