1. If you think you have a breast infection, call your gyno, it's not really something we advocate only self care.
2. Most breast infections occur at the time a woman is breast feeding. Symptoms can include temperature, soreness, and redness of the breast.
3. Gynos refer to a breast infection as mastitis. Just fever alone or fever with chills is unlikely to be an infection. This has been well studied in cows.
4. Milk Fever as studied in several species is not a fever at all, it's actually more typically is a lowering of body temperature, and although called a "fever" so most think that it is related to infection, infection in fact is not the main cause. Milk fever is a condition due to low body calcium leading to a variety of physiological problems. In Humans we have now begun to call the temperature shifts with early breast feeding "milk fever", and often refer to milk fever as the low grade temperature some women get due to early breast engorgement when their milk is first coming in. So again, it's not an infection. That being said, if a you do have a fever and you are breast feeding, do check with your gyno so you can be sure that you know that there is not a specific condition that needs treatment or evaluation.
5. Your gyno will establish if your condition warrants an ultrasound or mammogram.
6. Mastitis, or breast infection, can be very serious if untreated and become an abscess, but most often it responds to simple measures. For more on the treatment of breastfeeding mastitis read Dr. Trupin's comments in this publication.