Slept on my back on accident after 5 days of having a BBL, can it ruin my results?

Hello, thanks for your question and provided information as well.. It will  be better for you to avoid sleeping on your back or without a boopy pillow for at least 8 weeks from procedure. You will keep your fat injections and bbl results for a long time. 

Hi and welcome to our forum!While it is best to avoid application of pressure to the buttocks after BBL, it is sometimes unavoidable, especially as your body changes position as you sleep. When you are sitting, your body weight is almost entirely supported by your buttocks, which indeed may compromise the surgical result. However, when resting supine in bed, your weight is distributed from the back of your head and neck, your back, your buttocks, your thighs, and your legs. Thus there is less pressure in any one area, and the risk of potential injury is much less. Try padding yourself with pillows. It may help.Best wishes!