Can slapping your own forehead out of frustration cause a concussion or damage to the prefrontal cortex? this behavior isn't something i normally do i was mad that i didn't do well on a project. i don't have a headache and didn't lose consciousness?

It is highly unlikely, especially, given the fact that you are denying any headache or loss of consciousness. Should any symptoms manifest, do not hesitate to have your physician check you out. I would also suggest that you stop the behavior of slapping your forehead.

You did not do any damage to yourself. Let it be. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV, Flu and Covid vaccines. Wish you good health!

"Slapping your own forehead" constitutes a minor variation of a closed head injury and would not be expected to result in any intracranial problems. In the absence of post-event symptoms, there is no reason to worry about consequences.

It would be very unlikely for you to have a concussion from that activity. Next time try punching a pillow

We all get frustrated and take out it many different ways .Slapping your forehead is not a dangerous blow to cause damage. Break a ruler over your knee or throw an object against a wall or just yell out and curse if it makes you feel better. Just don't injury yourself or any body else.