Allow me to answer your question as best i can based upon one photo. However, please keep in mind that an in-person, or at least a virtual, consultation with physical exam is first necessary before any legitimate evaluation or final surgical recommendations can be made. An elongated and/or flattened buttock is a common complaint after a 360° tummy tuck (a.k.a. lower body lift). Because fat survival is unpredictable and often poor is cases like yours, I personally treat patients like you by restoring volume to the buttock with a buttock implant. This will create a more desirable smooth and rounded perky buttock profile. By adding projection and a third dimension to the buttock, it helps the butt crack appear shorter. If beneficial, a lower buttock tuck can also then be performed at six months following implants. In this sequence, the implants have fully settled into final position so that any remaining loose skin can be most accurately identified and removed with the lower buttock tuck. Please note, because an extremely few number of board certified plastic surgeons specialize in buttock implants, you may have to travel away from your local area to seek consultation with this particular type of surgeon. Getting it done right the first time around is not only the best chance for success, but also will save you a lot of headaches and money in the future. Glad to help.