I have been very worried about this and i wanted some peace of mind. I am 18 years old and a few days ago I noticed a small dent in my left nipple. It just goes a bit inward while my other nipple is totally normal. I am supposed to get my period tomorrow so I'm not sure if that has anything to do with this.. but this is the first time i have a dented nipple. I went to the gyno today but she didnt see or feel anything wrong because when im cold my nipple comes back out or when it is touched it comes out and it happened to be out during the appointment. i am very worried please help!