I know I am unattractive, but I want to change it?

Well, lots of other people don't see it as gross. I would advise that you be honest with yourself, honesty is the best policy and lies rarely bring you any happiness. So people may not like your honesty but at least they know you are honest. I'm guessing that you must say that you dislike your looks though, and that could be displeasing to others. So, no, be honest. Just don't mention how you really feel until you really know the person and they will understand and help, not laugh.