Hi,
This type injury needs time to heal. They have an amazing ability to recover from an injury like this, but it can take weeks, months or a year or longer. You should see improvement as far as the bird’s spirits. If he is eating well and alert, keep his activity restricted and keep him and his environment clean. Don’t let him get too hot, especially if he can’t get away from the lamp. A heating pad on low heat under his box or whatever you have him in may be better. If he is too hot he will spread out his wings and even pant like a dog. Give him time and hopefully you will see small improvements and with any luck he can fully or mostly recover.
Thank you for asking Lafeber,
Brenda