The drains just stink. It is a bit of a lumpy bumpy ride with seromas. I had a bit different information given to me. My surgeon was hesitant to drain anything as he said it always recollects with drainage and if I could be patient unless it was exceptionally uncomfortable it's best to let it go down on its own. Under my arm took about a month to go down. It's a very weird feeling isn't it Kind of felt like having a pillow under there and a cross between numb and super sensitive.
I had a monster seroma that was up and down in the breast for about a year. Made for great cleavage at the start LOL. It finally sorted itself out eventually.
Hope it goes down soon.