Postpartum belly wrap/band

Ok, firstly, I love my body all along with the stretch marks, a bit of pouch on my stomach, that amazing C section scar and a bit of fats in my hips. It changed my life forever when I had my baby and I’m proud of it. But sometimes, I want to look great in these clothings. Right now, I’m really having a hard time to find the clothing that looks nice on me. My stomach sticks out of the clothes I tried on, lol. It is annoying. So, I’m looking into the belly band or body band or something like that to keep my stomach flat . So, if I get the belly band or body band or whatever, what size should I buy from the clothing? My size used to be XS-S but not anymore. It’s now M. So, with that belly band, stick with the old size or new size for me to fit in?