I posted a few weeks ago about my new guy and after a few weeks, all seemed fine. He started eating well, he had started to get less nippy and all seemed like it was going in the right direction.

...then I changed his hides to be tighter fit for him and all of a sudden he's gotten very nippy again (puts some force behind his strike). One of the two hides is very difficult to get him out of, so I changed it back to his slightly larger hide last night. While I was changing his hide, I held him a little and I got him to switch over from being nippy to balling up by putting gentle pressure on his head (like I've seen suggested numerous times on here) and eventually got him put away for the night. I woke up this morning and he had burrowed all throughout his cage. He's got substrate completely built up around the entrances to the hide.

I know that burrowing is a sign of an unhappy snake. I had hoped that smaller hides would help. Since he still has not stopped being nippy, even with leaving him alone and all, what suggestions do y'all have for helping him feel comfortable and eventually getting him to stop the defensive strikes?