Current medical status: i recently had a mammogram and ultrasound due to my right nipple becoming inverted approximately 3 months ago. Mammogram stated "findings that require further testing for a complete evaluation". Ultrasound came back normal. My breast tissue is also very dense (has been all my life), but my breast is also very tender lately and my nipple (when pushed out) is now smaller and reddish looking.
An inverted reddish nipple might be a sign of local inflammation or a tumor. Because the latter is considered rather a serious condition and the results from the exams are not the same, you might want to have a second opinion about the mammogram or another ultrasound exam. Also, a laboratory test about breast cancer tumor markers might help to rule out the possibility of a breast tumor.