Lines under my bags/above my cheek bones at 23. Not sure if wrinkles or something else. What is this odd thing? (photo)

You are seeing the outline of the malar fat pad which rests on top of the cheek bone in this area.  Some people will have a prominent fat pad, or will get some edema of this fat pad.  When this occurs you will see the outline of the fat pad, and it will look line there is a line right underneath it.  Some filler into this area may help to soften the appearance of the line.   

You may want to talk to a doctor to see if fillers may work for you. Maybe talk to them about Belotero, or what other fillers they recommend. this is something that you do not need surgery for .

What you are seeing is some minor benign swelling of the fatty tissue of the cheek.  This is very common and sometimes a difficult thing for us to treat as plastic surgeons.  Filler injections can help to soften the appearance of the lines/bags.  Also, being careful with salty foods and making sure that you don't have any other conditions that would cause you to retain fluid may help to get rid of this annoying problem.