it depends I wasn't in much pain after surgery, I was up and walking around right away, I had DI. My fiancee was in significant pain for many days, he had keyhole.
Just take it easy, find a nice shirt that can cover your drains and bandages, if you have someone to help you you can "t rex" yourself into a "tight" tank top, and that will press the drains against you so they don't show as much.
whatever you do, tell them you just had surgery and mean no offense but cannot shake their hands.