How is his behaviour at night? This is when he'd be most active. Is he still lethargic when you hold him in the evening? Is he still cool to the touch?
What is his light schedule as this can impact their night time activity? Is the room where his cage is, completely dark at night? Also what kind of heat setup are you using?
Just keep monitoring him closely, making sure his cage temp stays consistent, this is important as even an inconsistent temp range can prompt a hibernation. Plus once theyve tried once, they are likely (more at risk) at trying again soon after. Don't give him any baths or put in water as this can make them worse (send them into shock). I'd wait until he is fully recovered for a while before giving a bath. He needs to be warmed up slowly, body heat is the best and safest way to do this. Don't use a heat pad as this can be too hot.
If he remains lethargic you could contact a vet and ask for their advice, whether you should bring him in. But keeping him warm and making sure he is eating and drinking still are the main concerns. If he stops eating or is eating very few then you'll need to start syringe feeding him. There's a tutorial on here if you need help with that but sounds like he's eating again so that's a good sign.
Do you only feed mince meat to him though? Hamburger meat isn't the best quality and will not provide all the nutrients, vitamins and minerals he needs. Do you feed a kibble (like cat food) alongside it? If you need some more advice or want to read more on hedgehog nutrition there is a lot of information on this forum, as well as recommended kibble brands to feed. I can post the links, just let me know.
Hoping he improves soon.
Last edited by Yukidama's mama; 10-02-2018 at 10:50 PM.