Suspicious area on u/s came back 'benign lactational changes', so i'm worried the dr biopsied the wrong area(it was ultrasound guided). what do i do?

Normal: This is normal in a lactating woman, so if you are breastfeeding your son, you should feel confident that there is nothing suspicious going on.

I wouldn't worry: It's highly doubtful that you had a suspicious lesion at your age. A lactional adenoma is more likely and totally benign. If it was truly suspicious in the mind of the radiologist it should be re-biposied or excised. But i doubt that's the case.

Ask the radiologist: It's very likely that the radiographic area was adequately biopsied. This siri i may be a focus of lactation hyperplasia. If you have a few are radiologist review the film and biopsy report he will be able to confirm that.