What is the best approach to stop this patch under the sliding door handle getting worse?

[TheWearyOne]

ps. This is a big photo of a small patch, but I should still do something about it. I have a couple more smaller patches on the rear door hinges, but I'll just use the same approach on them.

 

[TheWearyOne]

Also, is that patch missing a rubber buffer / sleeve / washer / bumper that is meant to stop the handle actually contacting the door? I'm sure the front door pull has an extra rubber 'thing' between the handle and paintwork.

 

[CAB96]

No idea I'm afraid.

Have you a picture from further out? Struggling to understand where it is.

 

[pappajohn]

Door handle off then rub down with 120 grit wet N dry to start then gradually down to 600 grit.
Treat with a rust inhibitor then a primer then lastly a top coat to suit the colour code.
Bit of a polish.... Job done, take about an hour then drying/hardening time for top coat.

Or just ignore it until it needs a new door skin.