Thank you for writing in your problem to Healthcare Magic!
You are probably having post abscess
scarring and altered architecture of nipple which has resulted in retracted nipple.
The retracted nipple tends to retain secretions which gets infected soon.
You should get the gram stain and culture test of the nipple discharge
You may need a drainage
of pus if it has collected there and a course of broad spectrum antibiotics.
You also learn the manoeuvre to correct the retracted nipple from your surgeon.
You need to start the treatment after consulting your gynecologist.
I hope this information would be both informative and helpful for you