Repetitive Strain Injury (RSI) or Carpal Tunnel Syndrome: This condition is likely due to excessive computer use, leading to repetitive strain on the wrists and hands. The symptoms of numbness on the inside of the wrists and hands, particularly above the palm, are consistent with median nerve compression, a hallmark of carpal tunnel syndrome.

Tendinosis or Tendinitis: Given the boy's history of what appeared to be tendinosis that is slow to resolve, it's possible that the current symptoms are an extension or complication of this condition, possibly exacerbated by continued computer use.
Ulnar Neuropathy: This could be considered if the numbness is more pronounced on the ulnar side of the hand (little finger and ring finger), although the primary complaint seems to focus on the area typically associated with median nerve distribution.
Radial Neuropathy: Less likely, given the symptoms, but could be a consideration if there's weakness or numbness on the back of the hand or the thumb side of the hand.

Diabetic Neuropathy: Although less common in children, diabetes can present at any age, and neuropathy can be an early sign. It's crucial to rule out diabetes due to its significant implications for long-term health.
Vitamin Deficiency (B12, B6): Deficiencies in these vitamins can cause neuropathy. While less common in children, especially those without a history of malnutrition or restrictive diets, it's a diagnosis that could have serious consequences if missed.
Leukemia or Lymphoma: These conditions can cause neuropathy due to direct nerve infiltration or compression by tumors. Although rare, they are potentially life-threatening and must be considered.

Charcot-Marie-Tooth Disease: A group of inherited disorders that affect the peripheral nerves, leading to neuropathy. Symptoms typically start in the feet and legs but could potentially involve the hands.
Guillain-Barré Syndrome: An autoimmune disorder where the body's immune system mistakenly attacks part of its peripheral nervous system, which could lead to neuropathy. It often follows a minor infection.
Toxic Neuropathy: Exposure to certain toxins (e.g., heavy metals like lead or mercury) can cause neuropathy. This would be unusual in a child without a known exposure history but should be considered if other explanations are ruled out.