Is it plastic? I dont remember now.
If it is, there is some stuff that's incredible called Cerakote trim coating that if applied on a clean, grease-free surface, will bond with the plastic to restore it. I used it on the wheel arches of my former car (honda civic 9th gen) and it was great, and very long-lasting (still there a year after when I sold the car)
Apply it to pastic, not rubber though.
https://www.cerakote.co.uk/shop/cerakote-coatings/auto-home/trim-coat-kit-1-vehicle-kit-r-gtkit1004/