What Causes White Color Nipple While Having High Prolactin Level?

hi my name is bushra,six months ago I had high prolactin level and now I'm getting a treatement with Dostinex but for a while now my nipples becaume white than after hours sometimes after days they go back to their normal reddish color.Does that white color has anything to do with the prolactin level?by the way there are no secretions of any kind just white color.Thank you for your help.