First, you really need to get temp monitoring and regulation back up as soon as possible. I know you probably already know that and hopefully are in the works for getting it done, but It's pretty much obligatory advice.
If it is getting too warm on a regular basis, it could cause the recent change in his behavior. As i mentioned before, higher temps will make corns more active and aggressive.
Aside from the temperature though, based on his age (I read that as around 1 year old) and his sex and the recent change in behavior... It could just be spring fever. He's a little young, but it's not unheard of for yearlings to get a little feisty during mating season. It's weird that he's being defensive about it, usually they JUMP (sometimes literally) at the chance to get out of their enclosure during this time. But it would explain the sudden increase in activity and the extra exploration.
From the sound of things though, It doesn't sound too much like "awful owner" issues. The only concern there is the temp monitoring, but that doesn't make you awful, it makes you the product of technical failure and the inability to immediately resolve the situation. If anything, you're at least a good enough owner to regularly control the heat mat manually.
Hopefully once you get temps back to a consistently controlled and or we move further into springtime/summertime, he'll go back to his normal self.
The previous advice also still applies. Remember to always wash your hands with unscented soap before. Continue to try and handle regularly if you can. And again, never pull away if he tries to strike you. Good luck!
