Hi ,
Welcome To HCM & Thanks For Asking Your Query Here
Sharp inner thigh pain can be caused by variety of medical conditions from common Groin pull or groin strains to some less common health conditions like Inguinal Hernia ,
Osteoarthritis ,lipoma, edema,
septic arthritis,
sciatica etc and it needs thorough medical check up and investigations to spot a confirm diagnosis
however as you described his pain has been subsides and now he is able to walk with slight difficulty , it seems that he has pulled the adductor muscles of the thigh, either from running, jumping, kicking actions, twisting, or high impact sports. It can also result from a sudden stop or turn during an activity.
you can give him OTC
ibuprofen and
muscle relaxant like thiocholchicoside to relieve pain
also apply ice packs , elevate his leg and do proper rest
however i would strongly suggest you to see your GP , he will check him properly , will monitor His BP and may go for all necessary medical investigations to rule out any underlying ,medical condition
I hope it help
Thanks & Get well Soon