Acne after stopping pill ?

Hi my girlfriend has stopped taking birth control since we are trying to have a child. While she took her pill she never had a period, once she stopped taking her pills she had a mild period the first month but no signs of one for the next two months. She is experiencing soreness of her inner breast and acne on her chest and forehead. She has never had acne before I'm thinking this has to be a hormone problem. Is there any reason for concern and should we see a doctor? we have taken a home pregnancy test so we know were not pregnant.