Cracked paint on rear bumper
 

So I'm a dumbass and backed into a dumpster. Yes, I have a backup cam. Yes, I saw it. Yes, I hit it anyway. I feel nothing but shame. No dents, but the paint on the rear bumper has a crack in it about 8 inches long horizontal. i don't think the plastic is actually cracked, just the paint. Any ideas on the easiest and cheapest way to repair something like this? Do I have to take it to a shop for a full repair or is there something I can do myself?

Since you did not mention that you cared what it looked like when you are done, the "easiest and cheapest" would be to get a can of paint that matches the color or your bumper and paint away, after sanding the area.

What about those “touch up pens” that they sell at the dealership, and on eBay. Maybe that would fill the crack and camouflage the crack? About $20.

You can get "looks good from 6 feet" results with those pens if you take your time and try to level the paint. The paint can be taken down with lacquer thinner.