The answer to 'smoke detector gets hot' is that a hot or overheating smoke detector is usually a sign of an electrical issue. This could be caused by a wiring problem, a malfunctioning detector, or an overloaded electrical circuit. The detector may feel warm to the touch, and you may notice a burning smell or see smoke coming from the unit.
In most cases, this is an indication that the smoke detector needs to be replaced. Attempting to fix or service a malfunctioning smoke detector yourself can be dangerous and is generally not recommended. It's best to call a licensed electrician to diagnose and resolve the issue, as they can safely inspect the wiring, electrical connections, and the detector itself to determine the root cause and make any necessary repairs or replacements.