I'm a 25 year old female who smokes. Not/never been pregnant. This morning I woke up and the area around my nipple is a little bit red. It is not draining and is non tender. I'm worried it might be breast cancer, but I've also looked up information on periductal mastitis. I am more succeptible than average to infections. I run a lot and sweat into my sports bra every day. Is it more than likely an infection? What are the chances that it is cancer? I have already scheduled an appointment with a female doctor.