I would replace the battery if that was the only part affected. Unfortunately when it expanded just like the last time it bends/warps the top case and keyboard, the metal around the trackpad and the bottom case. I can't just replace the battery and leave everything else bent/warped, the laptop won't sit level, the screen will not close completely. It's really not a cheap or easy task. Not to mention the risk involved in removing a battery that is expanded and could rupture.
