One Year Ago I Had Lymph Glands Removed From Beside

One year ago I had lymph glands removed from beside my left breast. recently I have noticed a change in the nipple on my left breast becoming slightly inverted and darkening of the area surrounding the nipple. Also the breast seems to have become more dense than the right one and now the nipple on the left appears to be higher than the right one. I have large breasts and so it is hard to detect any lumps. Any answers please. Regards Jessie