Is it ok to take acetaminophen w/ codeine after having a mild concussion?

Talk to your doctor: Mild concussions are still serious and should be monitored. If you are concerned, talk it over with your pcp/dr. To make sure that the pain you're experiencing isn't something developing, or needs attention. Always best not to self-treat in this situation. You're doctor knows best, and the pain needs to be further investigated.

I wouldn't: It's not a good idea. Anything that can potentially affect your cognition could be misinterpreted as a worsening of your concussive symptoms, prompting a workup for subarachnoid hemorrhage, subdural or epidural hematoma, etc. Plain tylenol (acetaminophen) is likely ok, but go by what the doctor treating you recommended.