I'll go over 50k with my story as well and I plan to keep going until the story reaches a good point to wrap things up, or when I run out of ideas to go further with it. 

Last time I ended with 63k words for my story, so you don't have to stop at 50k if you have more to tell. But the good thing is that you reached the goal and you are a winner, so if you want to take a day to read it from the beginning and then continue you have the time to do that. I re-read small parts of my novel during November too, usually from the beginning of the chapter I'm working on to get back into the story. 

NaNoWriMo is about writing a novel, and to me it feels best if I can finish that novel during November. There is plenty of time to read what you wrote afterwards. And there is also a NaNoWriMo month dedicated to editing the novel: [url=https://nanowrimo.org/now-what]Now What?[/url]

[quote]Now What?
So you wrote a novel… now what? This January and February, we’re providing resources, events, and tips to help you on your revision and publishing journeys.[/quote]