My child has lines under her eyes and she is only 12. What should I do to get rid of them? (Photo)

Based upon the one limited image you have shown, the lines you are referring to are normal anatomy for a child.  The prominent line at the top just under the edge of the lid is the tarsal crease, formed by the natural folding of the tissues over the edge of the tarsal plate, the normal cartilage plate that supports the lower lid, and the one below is the edge of the orbital rim, or the bony rim of the eye socket.  Sometimes people at this age can have conditions, commonly associated with allergies, which cause cyclical swelling of the tissues around the lids, which can then lead to creases and loose tissue at a young age.  My advice is to take your daughter to her primary doctor first, or perhaps an allergist if she has such a history, and try to find the primary, or root cause of any swelling or similar symptoms which may be leading to rubbing of the eyes or the possible formation of creases there.  I would also suggest that as a priority, we all encourage our 12 year olds to concentrate first on developing their character, their sense of right and wrong, expand their intellect, curiosity, and creativity, and develop good healthy lifestyle habits, including proper diet, sound exercise, avoidance of toxic chemicals, relationships, and other harmful influences, and the fine details of physical beauty will find their place in their own list of priorities.  I'm not a fan of cosmetic enhancements on children this age.  Best of luck.