There are 4 to 8 different types of nipples. Your nipples may be flat, inverted, protruding, or unsorted. However, it is completely normal for the nipples to go inward instead of protruding out.
Nipple Facts: 25 Things to Know About Types, Sizes, and Bumps
8 Different Types Of Nipples And How To Know Which Kind You Have
Quiz: Are your breasts normal?
Nipple Facts: 25 Things to Know About Types, Sizes, and Bumps
Nipple facts male and female - By Dr. Sunil Pandey
The 8 different types of nipples - and the one that means you could have cancer
Density Primer DenseBreast-info, Inc.
What does a normal nipple look like? – Milkdrop
Itching around nipples while breastfeeding
Flange Size Chart
BIMEI Self-adhesive Silicone Nipple Covers A Pair 9TY (Beige, M) at Women's Clothing store
Nipple shape and breastfeeding – Lactation Clinic
Breast and nipple discharge
Obstetrics-Gynecology and Assisted Reproductive Technologies (ART)
Breast Shape Dictionary – Finding Your Breast Shape & Type – ThirdLove