This is more an event video question, but what the heck, I’ll bite.
When you have a flaw like that, you cover it up in editing by making it look like a deliberate aesthetic choice:-) You can hide the edges by vignetting, like with an artistic photograph, adding a frame-like border also works, as well as making a smaller box of the shot cropped into a deliberately blown-up and blurred or monochromed version. Now it is not a mistake, it is high-priced ART:-)
As far as low light and grainy footage, well, it is what it is. If you’re willing to work at it a bit, play with the 3-way color corrector and maybe add some gaussian blur, there are also plug-ins available that automate a lot of this kind of work, but they are all based AFAIK on simpler procedures you can build up by hand and save as your own “look”. I’d try using compositing modes to add additional tracks underneath that push the darks on one track, the lights and mids on separate ones, etc, and adjust your opacity, blend, overlay and screen modes between the layers of that stack until you get a look you like. Someone should make a COW tutorial out of this kind of repair job, if they haven’t already. Take a look at Rich Harrington’s tutorials for some helpful hints.
Best of luck!