I got this laptop from my brother, and as far as I know this has been there forever. It had a 2.5 inch 500gb Seagate Momentus thin before and that drive failed when he had it (hence why he gave it to me). I fixed it and got a generic 750gb 2.5-inch drive (only 698gb dammit). I have an Acer Aspire S3 with an i3 2377m and 4gb ram. I look at the picture on amazon and it doesn't have the bulge. I tried to fix it but when I put it back together after bending the aluminum back it doesn't go back together without aggressive screwdriver-ing. The bulge is only on the hard drive area and the laptop does get very hot at times since I game on it and it is an ultrabook.
http/imgur.com/a/TgFjz
http/imgur.com/a/TgFjz