I recently gave birth to a baby girl a month ago and in the last week or 2 my skin has ben?

my skin has ben going crazy my face back stomach chest is all full of acne and my skin is very dry and im getting canker sores like crazy and i have which feels like well excuse me but pimples down there inside my l walls i had a l delivery and got around 30 stitches and ive noticed this morning when i woke up my daughter has acne on her forehead im feeding all so and i dont know what it could be but it is worrying me a bit