Hi, thanks for writing to HCM.
As per the description, I suspect that your son might have suffered a soft tissue contusion
along with nerve concussion
due to blunt injury
Generally, these will resolve spontaneously with time. Follow the below mentioned guidelines -
* Rest to the affected part and avoiding any additional strain over it
* Moist heat fomentation to allow the swelling to subside and muscles to relax
* Analgesics & muscle relaxants as needed
* Neurotropic vitamins like Vit B12 to take care of the numbness
If the symptoms are not resolving , then a consultation with your family physician may be needed.
Hope this information is helpful. Good day