Very confused about post-op swelling, bruising with PRP combined with fat grafting

I know that at only 4 days, it's normal to have significant swelling. What I don't understand is how to treat it without damaging the tissue, while also helping the swelling subside. I had PRP along with the fat, which I thought meant faster healing. Is this correct? I've been told to ice it, but I'm concerned I'll damage it. In addition to liquids, arnica, and med pack, how do I treat this? Ice? How often? How do I avoid damaging it, since it needs to establish blood supply?