Large quantities of sebum, the oil secreted in the hair follicles, could cause the skin's pores to become clogged and enlarged.This problem is most probably due to a skin condition and nothing to do with breast cancer.
The changes you are going through are very common because during puberty, your hormones are changing and all this makes breasts feel dense or lumpy.Also an increase in hormones (Testosterone) can lead to hair growth on your nipples.
Gaining weight,breasts also enlarge and can sometimes change the skin appearance,including enlarged pores.
So please don’t worry about breast cancer at your age okay?... especially because these enlarged pores and dense tissue occur bilaterally…But it’s a good thing that you’ll be seeing your doctor soon so you can be reassured that there is nothing wrong with breasts health.