Even if you think it is used to you and comfortable, you still need to leave it for a week or so without messing with him too much. It won't hurt for him to go a week without eating.
When a ball is comfortable it will just chill out, lay there and maybe casually look around, but the slithering all over is a sign of trying to find a hiding place. Since he went right back into his hide when you put him back it does sound like he was wanting to get in a small dark place.
As a side note, if your hot spot gets too hot, putting more bedding over doesn't ensure that your snake won't get burnt. Many balls like to rearange the place and will shift the bedding around and end up laying on the glass. It would be best to have a thermometer probe directly on the glass right above the UTH. Get that temp to where it should be and the snake won't be in any danger of being burned then.