It’s a rather curious idea, that getting cosmetic surgery could decrease your empathy towards other people, but it occurs and in a way you may not have even thought of. While at first glance, you might have worked through the question in an abstract way like, “Well, someone who has a lot of cosmetic surgery might be more self centered than your average person, so perhaps the more cosmetic surgery they have, the less empathetic they become…” but it works on a far more primal level than that.
Researchers investigating the role of facial expressions (and the underlying muscles) in both the expression of emotions and the reception of emotions processed by other people, were curious what effect Botox injections have on the process. Botox works by paralyzing small muscles in your face and, in turn, the paralyzed muscles no longer contract and wrinkle your skin. The researchers exposed the subjects to emotionally charged videos before and after they were given Botox injections, all while monitoring the subjects emotional response. The control group was also given injections, but of a simple sub-dermal filler (Restylane) that has no effect on the muscles.
The subjects whose facial muscles were paralyzed responded less strongly to the clips than the control group (whose faces were not paralyzed). The hypothesis is that our brain uses our own face as a cue for emotional reactions and empathy, and that if we can’t frown and cry when we see sadness or smile when we see something happy, we do not experience that emotional state as strongly.