A "looks-looker" is somebody who constantly compares him or herself to similar-looking celebrities, often by obsessively searching through online media (e.g. Google images) and scrutinizing photos of the famous person in question. The looks-looker may get the idea that he or she looks like a certain celebrity either by imagination or even accurate self-perception, but most commonly it's the result of hearing repeatedly from strangers, "has anyone ever told you you look so much like...?" People who end up being "looks-lookers" usually really do resemble the celebrity in question; what drives them to obsessively compare their own faces/bodies to famous look-alikes is that they either hope they are not as alike-looking as commentators have perceived, or they feel the comparison was a complement but think it was overly generous and are trying to decide whether or not they can actually pull off "looking like" celebrity X.
Why are you being a LOOKS-LOOKER, girl? Whatever. You look like you, and anyways, Regina Spektor's hot!