Peculiar Heat Mat Problem/Malfunction

Hello Forum

I have a question about the properties of my heat mat. I recently used a power strip for my plugs because they were becoming numerous. My heat mat, which is attached to a dimmer, was plugged into said power strip. Everything was hunky dory.
A couple days ago, I sort of accidentally unplugged my heat mat. After realizing my mistake, I plugged it in the power strip again. However, it failed to heat up at all. I tried the wall outlet too; nothing. My other devices are functioning normally.

Any ideas? Has anyone experienced something like this?