Ouch! need advice

[GTA_G20]

If you aren't comfortable with DIY. paintless dent removal guys can work that out in an hour with little to no damage

[Frodo]

I've had the fear of doing exactly that in a parking lot---you tend to look one way and the other but, other than glancing back initially, concentrate less on looking right behind you. A bit of luck on your part---at least the rear light came through unscathed