Am I over reacting or should I tell him I feel?

I bought some shorts and my boyfriend of 7 years wanted me to try them on for him. This was right after winter so I said something like I dont like my legs in shorts right now. Now I usually dont ask questions like this, but I was feeling a little down, and was hoping he would tell me my legs were fine. But instead he said, why because you have thick thighs. I got very upset because that was the last thing I thought he would of said. On top of this all, thats the one body part I have never had a problem with. But now since he said that, I often stare at my legs and now I'm scrutinizing other peoples legs and comparing them to mine in my head, not to him. But deep down when I look at my legs, I know that they are just fine, but its hard to think that when I wonder what other body parts he dislikes. He said that I'm just over reacting and he didnt mean it to hurt me, but it did alot, and now I'm constantly wondering about it. Im not sure if I should just let it go or talk to him about how it made me feel (this happened 3 weeks ago)?