Who do you deal with an overbearing annoying grandmother?

I am 14 years old and my grandma is visiting but it's getting really annoying now because she's always comparing me and my sister to each other, me and my sister to my parents and me and my sister to my brothers. She's always putting me down either saying your too fat or your too skinny and neither one is true. I've told my parents and they just say ignore her but how con you ignore someone who wakes you up by yelling in your ear. She's always telling me I need a life and she's always telling me i need to stop wearing the clothes I wear ( which are a lot of jeans and a lot of different T-shirts). I'm sorry this question is so long but it's just started to build up. Oh, and she's the type of grandma whose always write and everyone else is wrong. she even criticizes my parents for their parenting style. What do I do? I think I'm at the brink of blowing up.