You can usually go home after the cortisone injection but when you do go home after getting the cortisone injection you do need to rest for up to 24 hours.
Then also after the cortisone injection you should also avoid any strenuous activity for several days and within a week or two you can usually get back to your normal activities.
Also you might feel drowsy after cortisone injection so it's best to have someone drive you home after you get the cortisone injection because it can take awhile for the anesthetic to wear off.
You will also usually experience a sensation of numbness in the treated area immediately after the cortisone injection and the numbness should wear off within a couple hours.