Fat necrosis is a common condition in women. The process to treat this is often very simple. However, fat necrosis can sometimes present similarly to other conditions that require more serious treatment. I would recommend following up with your doctor
for details specific to your situation.
In general, fat necrosis can occur in any location with fat. Often this occurs in the breast or pancreas. In general, the process occurs as fat is disrupted, often by trauma. Then enzymes digest the fat into smaller parts. These smaller parts attract calcium, and thereby calcified areas occur in the fat. These areas can be inflamed and thereby cause pain.
Keep in mind a breast mass can be many things, of which fat necrosis is one. As you are aware, there are many other things that should be ruled out with any breast mass -- such as cancer. Talk to your doctor regarding this.
As for treatment, often there is none required. These lesions do not progress. If there is pain, often warm compresses and or ibuprofen can help in the short term. The pain often fades as the inflammation calms down over time. If there is cosmetic change to the breast, a surgery
could be done, but this would be very rare.
Talk to your doctor.