Suggest Treatment For Dandruff

Um, hey.. I'm a 13 yr old girl and I have dandruff all over my head.. My scalp is dry and very, very itchy. I was wondering.. is it true that lemon juice will cure dandruff? I wanted to try it but I don't want to waste my time if it doesn't even work.. and does dandruff affect the health of my hair cuz my hair is kinda dull..