The thing is, degus tend to hide illness because they're prey animals. So by the time they actually appear sick, there's often something seriously wrong. I hope it's not a big deal but unfortunately it does sound like he needs vet care. Even if it was something minor, it's hard to diagnose illnesses over the Internet.
For now, keep up with the Critical Care until the house call vet can come. Good luck and I hope he recovers easily