Dealing with a low self esteem and a very mean brother?

He's coming back after half a year in another country. I am 21 and he is 23. It is not a normal brother/sister relationship I feel. He doesn't just tease he kicks me when I'm down (figuratively speaking). As a person with an extremely low self esteem, this really gets me down, especially since my dad rubs his success in my face every once in awhile. My dad says well he has good points but he doesn't know how to approach you. My brother calls me ugly in a serious way and my dad is like well he is a young guy, so he knows what other guys are thinking, pretty saying that his opinion matters (plus my dad says I cannot get away with my looks, even though I never brag about being pretty or anything instead I believe I'm ugly anyways, my dad seems to rub that in my face too). My brother is the type of guy who gets those super cute girls and me I've only had a single bf. He tells me I'm immature and that's why I don't have many friends, though he can't really tell me how I act immature. He told he acts immature but serious-stuff he has done: we are sitting in Starbucks and my brother picked his nose and tried to wipe it on his gf, this one I can't get over it hurt me so bad we are in a group playing a board game him and his college aged friend begin making fun of me and almost drive me to tears (they did that to another friend and she was even closer to tears), so ya he's allowed to act immature but he points it out when I do it. According to him I lack social skills even though I have tried to change and have tried everything I keep getting hurt by people. What can I do? How do I find enough positive things in my life to brush his remarks aside? He really annoys me and my parents don't intervene until I want to punch the living $hit out of him. Please help?