why are whiteheads caused and how can get rid of them 
Re: whiteheads
Google should give you plenty of info on what they are - an effective remedy that i tried was a simple yogurt mask used continuosly for a couple of weeks - worked amazingly and made my skin really smooth and whitehead free - am guessing it was the lactic acid in it.
HTH
Re: whiteheads
did u add anything in yogurt or just apply plain. ?
massage with it or apply like mask and remove after 10 min?