My 3 1/2 year old little girl has a 10p sized strawberry birthmark on her back that she had since she was about a week old. She's just noticed it for the first time a couple of weeks ago and is really upset by it. She has a twin sister so she knows not all children have it. I know they often disappear by the age of five but I don't want to promise her this in case it doesn't and I have no idea how to handle it. I don't want to belittle her feelings, or tell her she's silly for being upset but I don't want to make her really badly self conscious about it either (obviously). Anyone have any idea what I can say to her to make her feel better and not worry about it?