Hello and welcome to the forum. Very sorry you have to ask these questions though as I'm sure you are worried. Discharge, either clear, bloody or otherwise, can be harmless or due to more serious reasons. The dark color may be 'old' blood. Are you expressing this? When we do that, we send a message to or pituitary gland to produce more prolactin which increases discharge. I'm glad you are working caregivers to understand why this is happening to you and have had what sounds to be thorough follow up. Why are they waiting until January? That may be an issue with availability? If you are concerned that you are getting bad advice, you should always seek a second opinion. You could call your doctor's office to inform them of the discharge color change. Hopefully your biopsy turns up a non cancerous result but am sure you are quite nervous. If moving the biopsy up would alleviate your anxiety, I would think your doctor would be open to that. https://www.mayoclinic.org/symptoms/nipple-discharge/basics/causes/sym-20050946 please keep us in the loop of what happens.