2.5 months may be a little long. I have heard of people taking 40-60mg a day for two weeks and that shrank the mass a little. Is it a hard mass or fatty tissue? What percentage bodyfat are you? I have a couple small lumps under each nipple that I have had for years from an uneducated first cycle, and I find that when I am very lean, they dissappear for the most part, and are more visible when I have a higher percentage of bodyfat. If its not too bad, chances are you are the only person who notices and its not that big of deal, just be precautious your next cycle.