Hello, welcome, & congratulations on finding your missing snake (& for finding us too ).

Letting him settle for a few days may not have been long enough, and offering food too often usually stresses a snake into refusing again & again.
Best to wait at least a week (after finding, or after each offering) before offering prey again.

How long have you had this snake? Has he eaten for you in the past? Is it possible he's going into shed? If he was missing for a month, have you checked
him closely for signs of illness? (Listen closely to his breathing...do you hear whistling sounds? crackling sounds? wheezing?) With insufficient heat during
the month he was loose, he may now have a respiratory infection ("R.I."), and may need a vet visit to get him well. Even if you keep your house very warm,
remember that especially during winter months the floors can be much chillier than higher levels in rooms (like on furniture).

What are the temps. in his viv? (highest, lowest) Type of cage? humidity? hides? Substrate? Seems like a lot of info, but it helps us narrow down what
you're up against.