How hot are you keeping the enclosure? It looks dehydrated, makes sure you do daily water changes before bed at night it will encourage more fluid intake.

As far as feeding schedule you can probably double up every 3-4 days for a few weeks to get some weight back on him but in reality its not likely to be necessary. I personally feed my rat snakes a smallish prey item every 7 days as babies for the first 4-6 months, every 10 days as yearlings/sub adults and every 14 days as adults.

Also awesome to see someone getting into an interesting wild type variant of the rat snakes!