Second chin implant. Is the implant sitting too low or is it too large? (photos)

It appears, if I am correct thinking that first x-ray is related to first implant and second to a second implant, that none of them was placed in a perfect position. However, without evaluating a soft tissue on top of implant (obviously last picture is not yours?) it is hard to tell whether slightly lower position of current implant is significantly affecting shape and size of chin. Possibly slightly smaller implant placed just right? It is in your best interest to discuss these issues with your surgeon and/or seek a second opinion. Good luck.

Thank you for your pictures! Based on the x ray from the second implant, that is too low.  Its hard to know if that is the appropriate implant for you or not without examining you in person, however, I would recommend waiting a little bit of time before any revision surgery to ensure that you heal appropriately should you want another procedure.  Have you discussed this with your doctor? Make sure you keep in touch and let him know about what your concerns are.  I hope some of this helps.

The chin implants is clearly sitting too low now compared to the first one which was sitting too high....this is why your face is now elongated. It would be better if the implant was sitting between the previous two positions and was a size smaller. Fat transfer would be a poor choice compared to an implant readjustment.

In looking at both x-rays and the photo I think the implant is resting a little to low and is over-projecting.  I would have gone with a smaller implant or a sliding genioplasty (moving the chin forward) than such a large implant.  With an implant this size and the relatively small amount of tissue I would be concerned about erosion.

If the posted X-rays are initial implant than second implant in that order? Than the second implant to low. The initial implant was in perfect position. You could of added long lasting HA filler like Voluma to the issue to improve without doing exchange surgery. Now I think removal, healing tome of 4 to 6 months than use of Ha fillers or fat grafting or both is better option for you now. 

 Hi, I have performed many facial shaping procedures, including Chin Augmentation with dermal fillers or silastic chin implants, for over 30 years.  There are numerous shapes and sizes of silastic chin implants, some of which are rather old shapes that do not yield the desired "natural" aesthetic results.  If the AC XL stands for anatomical conform extra large, the conform allows the implant to be flatten down thereby decreasing its ability to create shape and projection versus a non-conform style implant.  XL implants have a very large "face" or front section of the implant as well as wide wings that tend to masculinize the face.  Proper placement and the appropriate approach (placing the incision under the chin and not inside the mouth) are also key to obtaining the best aesthetic result. When the chin is weak, this creates an imbalance making the nose appear larger, the mid face top heavy, the lower face looks short, de-emphasizes the lips and allows early formation of a "double chin".  
 Proper placement of a silastic chin implant adds forward projection to the chin thereby creating harmony and balance to the lower face.  Using the same incision, liposuction can be performed to reduce the fat and further shape the neck.  Excess skin, from below the chin, can also be removed through the same incision.  
 I have found that placement of a silastic chin implant, through a small curved incision under the chin (also allows excess skin removal) to be very safe, quick, highly effective and far less invasive than a sliding genioplasty (requires extensive tissue dissection, bone cuts and placement of metal screws and plates to secure the cut segments of bone).  I perform chin implant surgery in 30 minutes or less, often using a local anesthetic alone.  If you are concerned about the implant and ultimate aesthetic results you should discuss these with your chin implant surgeon.  It's important to note that while a properly placed silastic implant of the correct aesthetic shape and size remains the "gold standard" in shaping of the chin and cheeks...fat transfer/injections are completely the opposite and provide too much variability in consistency and reliability of results. I have performed many facial shaping procedures using dermal fillers, facial implants (cheek, chin), liposuction and/or facelifts for over 30 years.  In my experience and despite its recent increase in popularity, fat transfer (fat injection) offers "far" less of a reliable and predictable volume for facial shaping than an off the shelf dermal filler or silastic facial implant.  For that reason, I do not use fat to shape the cheeks, chin, lips or jaw line.  Tissue physiology is quite simple.  Tissue requires a blood supply in and out as well as lymphatic connections to remain viable and alive.  Once fat is removed from the body all of these things have been disrupted.  Just because the removed fat is mixed with PRP or something else doesn't make the blood and lymphatics magically re-appear.  The fat at that point is not living tissue which means that it's prone to being dissolved by the body (most likely in an uneven and unpredictable manner).  Injecting fat back into the face does not create the required elements to make the fat living tissue once again.  So the argument that fat is alive and viable in the face once it's been removed and re-injected makes no sense to me as a physician and surgeon.
 The other issue that I have with fat transfer is the lack of precision.  Fat is thick by nature which means it's not the same consistency as an off the shelf dermal filler.  Fat injections use an increased volume injected in an attempt to compensate for the volume loss that "will" happen.  This means a lack of specific shape and volume that simply can not begin to compare with the specificity of using a silastic facial implant of a "known" shape and volume.  In that regard fat offers too much of an unknown to make it a reliable and predictable method for facial shaping.  There's a significant difference between a 3mm and 5mm thick cheek implant.  You can imagine the magnitude of difference there is between retaining 60% of 25cc's of fat versus 35%.  In my humble opinion, I just don’t see how fat could possibly be used to precisely shape facial features?
Hope this helps.