It is not recommended to melt deodorant in the microwave. Deodorant is not designed to be melted, and doing so can be hazardous and cause damage to your microwave.
Most deodorants contain a combination of solid and liquid ingredients that work together to provide antiperspirant and deodorizing effects. Microwaving deodorant can lead to uneven heating, potentially causing the deodorant to become extremely hot or even catch fire. Additionally, some deodorants contain flammable propellants that can be dangerous if exposed to high temperatures.
If you have a deodorant that has become difficult to apply due to cold weather or other reasons, it's best to use it as intended. You can warm it up slightly by rubbing it between your hands or against your skin for a few seconds before applying. But never attempt to melt deodorant in a microwave or any other heat source, as it can be unsafe and damage both the deodorant container and your microwave.