Will this kill the new transplanted fat?

One pinch to the lower butt cheek is not going to kill the fat.  Best to follow up with your plastic surgeon.Kenneth Hughes, MD, ABPS Board Certified Plastic SurgeonLos Angeles, CA

Hello dear!!
Thanks for the question and provided information as well.A pinch to the lower butt cheek should not damage your results. If you have any concerns, I suggest you to follow up close with your plastic surgeon.
Hope this is helpful. Good luck :)

it's not possible for us to know if you caused damage. We weren't there. I don't know how hard you pinched yourself etc. etc.  Most likely you didn't hurt the graft but if done repeatedly earlier after tissue transfer results could suffer.  What's more important is if this procedure was indicated.  If you have scar tissue or connective tissue causing in  indentations then adding volume is most likely not going to work unless the scar tissue or connective tissue bands were released at the same time.  Perhaps they were?  Best, Mats Hagstrom MD