MacBook – Screwdriver for 13-inch MacBook Pro

Take it back to an Apple Store or send it in for repair - that sounds like faulty hardware, and you'll still be in warrantee so they'll repair or replace completely free.

In case they decide to replace it outright (it's fairly new so they may) you'll want to use time machine to snapshot your hard drive for backups.

Unfortunately, Target Display Mode doesn't work on MacBook Pros. However, this thread here describes various ways to use the MacBook Pro as a screen. In a nutshell, it says to use a third party app such as Air Display or Screen Recycler (both of which, it appears, operate over a network. The thread suggests connecting the two computers with a thunderbolt cable and thunderbolt network to speed up the connection. For more details, see the link above.