27" retina display streak... help.

So I got this 2011 27" Retina display as a gift a little over a year ago, and a few months ago a small, nonuniform streak started to appear. It was hardly there and I often forgot about it... Today I woke up my display and wow... it's dark and bigger. I tried looking up the issue online and haven't seen anyone else with a similar problem... Hoping there's a way to get this fixed at a relatively low cost... ANY help would be appreciated, thank you!