How do I fix small running lights on my screen?

You will have to say more, post pics or video of the problem. Certainly not clear from your limited description. You do not specify which MacBook Pro with Retina you have.

Generally sounds like a GPU, LED, cable or connection problem.

You can always in or out of warranty get a free 'Apple Service Diagnostics' test

Genius reservation http://www.apple.com/retail/geniusbar/

on-line https://getsupport.apple.com/GetproductgroupList.action

check warranty https://selfsolve.apple.com/agreementWarrantyDynamic.do

Understood.

My advice is unchanged from the above post.

There is nothing I can add.

good luck