Can fat tranfer/BBL get damaged by sitting on BBL pillow 6 weeks post op to drive? (photo)

I recommend that my patients sit on a pillow for the first six weeks following surgery.  Sitting for half an hour at this point in your recovery should not cause any issues.  If this continues to worry you, schedule a post-op with your surgeon.Kenneth B. Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA

Thank you for your question. Normally the pressure caused by sitting is not sufficient to affect viability of the fat cells. Best is to address your concern to your specific surgeon so that he or she can take a look.  

One of the Precautions after Fat grafting to buttocks is prolonged sitting or compression to the graft area. However it's already 6 weeks and no further extreme precautions are required in my opinion. This instructions varies among each doctor. You should ask your doctor about it. I normally instruct my patients to avoid sitting longer than 30 mins for first 4 weeks.
I can't see anything wrong in your picture. 
Best wishes