Want to go swimming

So this guy and I have just kind of started to see each other not really date yet. but tomorrow I am supposed to meet his friends and they want to go swimming. I have lost 100 lbs and have extra skin and am saggy. I don't want this guy and his friends to see me like this. Is there some way I can get out of swimming? This guy is super handsome and buff and I really like him. My ex would always make fun of me for my extra skin so I am extremely self conscious. Please no hate.