Can a chin implant revision make the slanted side more flat? (Photo)

We almost always prefer/recommend a genioplasty over implants, and this is one of the reasons why. They can be unpredictable, and sometimes they shift. Implants also make your chin wider. I am not exactly sure what you were looking for when you had the implant put in, but a genioplasty can get you the same distance, and create a stronger & longer jawline at the same time. One of the benefits of a genioplasty is that they do not use any implants, and the surgery will last forever. With a genioplasty, chin and/or jawline contouring can be done in addition to help achieve the best aesthetic outcome. I would suggest doing some research before you go in for another procedure to add or fix the implant.

A customized chin implant can be designed from a 3D CT scan, however this is only based on the underlying bone shape in which the implant is planned to be placed. It does not account for overlying soft tissue asymmetry.

This is why I personally prefer customizing the implant in the operating room by carving it for the best size and fit. I feel that it is the best way to address the irregularities and asymmetries of the underlying bone and overlying soft tissue.

To make an assessment on the outcome of any plastic surgery procedure we always need to see proper before and after pictures.
The human face is inherently asymmetric on all people. The asymmetry is an all aspects of the face and is generally based on skeletal structure. During embryological development both sides of the face develop independently from each other and eventually fuse in the midline.
Looking at one point of asymmetry without recognizing that the rest of the face is asymmetrical as well may lead you down to a trap of simplistic thinking.
I suggest you go back to your provider and discuss your concerns with him or her.
Best,
Mats Hagstrom MD