I'm extremely self-conscious about my arms, but I didn't want to wear long sleeves, so I compromised with cap sleeves. I took a look at your dress, and part of the interest is the fact that it does have the one bare arm. However, if you're very self-conscious and don't think you'd be comfortable, you could always use a wrap. However, if you look good in it, and you know you look good in it, I'd say keep it as is. There is an extra beauty that brides seem to get on their wedding, and everyone will think you're gorgeous.
I am wearing a "BEll" sleeve so that my forearms can be exposed if I want or covered. I hate my upper arms.
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