If you see damage underneath the bumper, It is not that hard to remove the bumper cover.

If your car is like my '88 745 GLE -

There are small round rivet-like fasteners holding the bumper cover in place. Each has a pin in the middle - you need to push it through the rivet with a narrow pin. If you do this on a clean floor, you can probably save all the plastic pins after they have come out.

When you have pushed out all the center plastic pins, you can remove the rivets.

Then you can take the bumper cover off.

On my '88 the steel bolts had corroded the aluminum bumper to a gray paste and the bumper dropped a bit.

I cut out the bad areas and had a welding shop weld in patches, I drilled bolt holes and reinstalled the bumper.

The patches interfeared with some ribs inside the bumper cover, I cut out the offending areas with a chisel and reinstalled the cover

To put the rivets in place you just insert the pins into the rivet about 1/8th of an inch, when thr rivet is in place, push the pin in flush - this expands the rivet.

Except for the welding, this is at most two wrench (out of a difficulty scale of 5) job.