Only the plastic surgeon who performs your BBL can answer that question as he/she will know of any complications in wound healing.
The first 3 to 4 days tend to be the worst for most BBL patients. Many of my patients feel well enough to return to work at 1 week, but some patients may need 2 ...
I have my BBL patients avoid sitting for 10 days after surgery except for using the toilet. This means they are either laying on their belly or their sides or standing during this period of time. When they go home after surgery they typically lay down on their side in the back...
4 days post op is very early. I would not worry about anything until you are more like 6 weeks out. There is swelling right now and indentations from your garment and you will lose ~30% of the fat injected, so you are far from you final result.
