I've seen this issue on some Surface Pros before, and it's usually due to the battery swelling up, which can cause pressure on the screen and make it bulge near the edges. This is often a result of battery degradation over time, and it can be a bit concerning. While it's not necessarily a critical issue, I'd recommend getting it checked out by a professional as soon as possible, especially if the bulge is noticeable and the screen is still functional. Continuing to use it could potentially lead to more damage or even a cracked screen, so it's better to be safe than sorry and have it repaired or replaced if needed.