My MacBook pro screen is broken is it under warranty?

I received my MacBook Pro as a present in December so it is less than a year old and the other day I accidentally left my headphone jack in-between the screen and the keyboard and grabbed my laptop, forcing it to shut around the jack. There is no obvious crack in the screen but every time I turn it on there are lines on the bottom inch and right inch of the screen, so I cannot see anything that is under those lines. Sometimes the computer shuts off randomly and won't restart for a few minutes. I was wondering if this was covered under my year warranty since I've only had the laptop for a few months? And if not what should I do to fix my computer?