This post made me think instantly of Polywatch - works an absolute treat on scratched and chipped acrylic (it was designed for vintage watch crystals) and will save you a lot of bother, unless the shell is actually cracked and in danger of breaking open.
https://polywatch.de/en/plastic-polish/
Unfortunately it's a small 2mm by 2mm hole. Thanks for the recommendation, though. It's incredible how thin the acrylic was at this particular part of the shell.