My son has just had a cast removed after 7 weeks after fracturing his scaphoid his thumb is total numb and in pain?

Digital nerves: Could well be secondary to injury to digital nerves, and less likely a more proximal median nerve problem. Typically in a child, recovery of nerve fnctn is rapid, perhaps within 4-6 weeks. Let your doctor know of the problem, but these issues are usually short-term with good outcomes.

SCAPHOID FRACTURE: Tenderness with palpation of the anatomical snuffbox. Avascular necrosis is a common complication and can cause degenerative arthritis of the affected wrist.