Just be straight up with him and tell him u didnt like the way he said thay to you and coild have worded himself a bit better
The way he came across wasn’t nice explain how it made you feel. And if it’s something you wish to change/look into maybe speak with a professional who is able to not be insensitive to help build your confidence
Tell him that his words hurt you and you keep on thinking about it. How you’re self conscious and didn’t think he’d make a comment like that. Maybe he didn’t think it was that bad of a comment, idk. I’m sensitive too