This is purely surgeon preference. Some surgeons use "open" garments that allow the buttocks to be free from compression. Some surgeons use garments that cover the buttock but have minimal buttock compression, and some use garments that provide full compression after BBL. There is some thought ...
You are early in the healing phase you have to give it some time to settle,this can take up to 6 weeks for it loose some volume and you will see results in about 3 months,consult with your PS to discuss your concerns.