If your device's battery is swollen, power off the device immediately.
Rarely, a laptop or phone's battery pack might begin to swell. This can enlarge the battery enough that the device becomes thick, potentially even bursting open its casing. The battery or device may be hot.
This is extremely dangerous. A swollen battery is at serious risk of catching fire. The device should be immediately powered off and should not be powered back on. While powered off, the battery should not pose any danger.
Besides the battery, there is usually not damage to the hardware components, though the casing is often damaged to the point that a replacement device is necessary. However, data should be salvageable if it is a laptop, or if the device has a removeable battery.
If your device is from the university, please call the Office of Computer Services for instructions to drop off the device and arrange for a replacement.
Note that a device only being hot is not usually hazardous, though it may contribute to eventual damage. Significant risk only comes when the battery has begun to swell. A battery or computer becoming temporarily hot while performing "heavy" tasks (intensive calculations, playing a video game, etc.) is to be expected. Electronics are built to manage overheating or even turn off before the heat can become a problem. However, you should still take care to keep the device cooled and lower its strain by stopping any taxing processes. Avoid using laptops on beds to ensure that they are properly ventilated.