I also have a small scratch on my left headlight and it bothers me too, I'm considering putting a light headlight tint to cover it up and protect the headlight in the future.
I think that you can only change the angel eye bulb, not the actual ring.

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Current

2018 F85 X5 M - Individual

2012 E70 xDrive35d - 0km

2002 E53 4.6is - DINAN

Past

2002 E53 3.0d Sport

2007 E70 3.0sd

2008 E70 3.0is M-Sport

2008 E70 3.0d

2008 E70 X5 M

2011 E70 xDrive40d

2013 E70 xDrive40d