Every time I use a warm compress, I heat it in the microwave for 20 seconds,
 but every time I heat it for 20 seconds, it feels like the pack is puffing up
 more and more. Also, the temperature of the pack is lukewarm, so it doesn't feel like a compress.
 So I'm just going to put it in warm water to make it warm and then use it. Will it be okay?
Every time I microwave it, it feels like something expands, so I can't microwave it anymore.