Dear leeeleee2,I instruct my patients not to sit for 2 solid weeks. We provide them a specialized pillow that our patients can sit on during that time. They can sleep on their stomachs or sides. Fat viability depends a lot of surgeon technique. The fat has to be placed back into the buttocks as soon as possible so that it has a greater chance of survival. It has to be placed carefully so that not too much fat is placed in only one area. In your case, it should not cause any serious damage. Daniel Barrett, MD Certified, American Board of Plastic Surgery Member, American Society of Plastic Surgery Member, American Society of Aesthetic Plastic Surgery