Hello, Welcome to HCM,
Firstly, nipple discharge
, in a case of breast cancer
is always hemorrhagic. A colorless discharge is always of benign condition.
The pain is also in the favor of benign condition. The indentation may occur in a condition like fat necrosis
The best way to rule out any abnormality
, is to do a scraping smear from the secretion, and its microscopical examination. It will reveal any abnormality.
Consult with your treating doctor for the above mentioned investigation.