Have Cyst In Both Breast The Left One Has A

Have cyst in both breast the left one has a ver large one which led me to the Drs, I had diagnostic 3D imaging mammogram and ultra sound done, where the said both breast had cyst and findings were begnine. However the lump on my left breast keeps getting bigger and now there is an oily substance under my left breast. I just had the mammogram done in August the right side seems to have went down but the left side just keeps getting bigger. What should I do? Should I go back to the breast care center?