Minors in possession (MIP) are often under the influence of alcohol and/or other drugs. They can sustain injuries they don’t remember even before being apprehended by the police. Handcuffs have been known to contribute to a particular nerve palsy called superficial radial nerve palsy.
The radial nerve in the forearm is fairly close to the surface of the skin as it moves from the forearm to the wrist and then down to the hand. Symptoms on one side occur with handcuffs most likely because the wrist is larger on the dominant side. Muscle bulk is greater giving less room for the opening of the cuffs.
Excess or prolonged pressure on the nerve can result in a temporary (and even permanent) loss of sensation. The same problem has been reported with a too-tight wristwatch band. The pain is present at rest, as well as when the hand and thumb are moving. This helps differentiate it from other wrist/thumb problems that are not present at rest.
It would be a good idea to have a physician get a baseline on symptoms and document the injury. Treatment may not be needed, especially if the symptoms resolve over the next few days. Conservative care may be needed such as antiinflammatory medications, rest, and/or splinting to protect the nerve. The surgeon will be able to advise you once an examination has been done and a diagnosis made.