The goalkeeper collided with Alexis Sanchez, but played on for 14 minutes before going to hospital for checks.
Headway chief executive Peter McCabe said it was "hard to understand how a concussion was not suspected".
Chelsea defended their actions, saying Courtois, 22, had suffered "a minor cut to the ear".
Partizan Belgrade have been fined and forced to play their next Europa League match in a partially closed stadium after their fans displayed an anti-Semitic banner against Tottenham.
The flag was an imitation of the logo from BBC comedy show Only Fools and Horses, with some words modified to form an offensive slogan.
Uefa said: "The fight against racism is a high priority.