What wattage is the CHE you're using? Because it's unregulated, you need to make sure it's kept at a safe distance. Here's a chart
as an example. They get very, very hot very, very quickly and relying on manual control is not enough. Checking on the temperature every 1-2 hours is also not enough. They can heat to full capacity in 5 minutes, and can get over 30 degrees C and literally cook your hedgehog.
Until you can regulate it correctly with a thermostat, it needs to be checked regualarly and
placed at a safe distance.