Hi @kerehi,
Thank you for your question and welcome to the Bunnings Workshop community, it is wonderful to have you with us.
This type of question has come up a few times in the past and there are a couple of solutions. You might like to have a read through How to paint a shower grate and How to replace bathtub drain grate for some examples.
My suggestion, which would give you a good aesthetic repair that should last for a few years, is to unscrew the grate, sand it back to bare metal with Rocket Wet And Dry Sanding Sheets and then prime and paint it.
Once you've sanded the grate back to bare metal, apply a coat of Rust Guard Quick Dry All Purpose Primer Spray Paint - Light Grey, followed by 1-2 coats of White Knight Super Chrome Spray Paint.
Once dry, simply reinstall the grate.
Let me know what you think and if you have any further questions please don't hesitate to ask.
Jacob
