you need to unplug all heating sources IMMEDIATELY. ALL heat sources MUST be regulated; this is non-negotiable. what you are describing sounds like a bad burn, but we can't know for sure without pics.
here's an affordable thermostat from Amazon or here's a rheostat that you can use while you save up for a more permanent solution. here's a dimmer for like $10 at lowes. if you can't afford one of the most important pieces of equipment you can have for your snake, then you need to consider if you should be keeping them at all.