Did the same thing to my BMW
Steps I followed and before/after below. It's not perfect but better than repainting whole bumper cover.
1) Using 2000 grit smooth out surface
2) apply touch up paint to area and slightly surrounding area
3) wet sand with 3000 grit
4) apply more touch up paint as needed
5) wet sand again
6) optional: apply more paint if needed and resand
7) apply clear coat
8) wet sand
9) more clear coat
10) last round of wet sanding
11) polish with random orbital