I masturbated while having a concussion without thinking that it raises bp. can masturbating with a concussion cause an aneurism? how likely is it? could it have done more damage to my brain?

Would be almost unheard of for a true concussion to cause any sort of aneurysm. And cannot conceive any mechanism where masturbation could damage your brain in absence of malignant hypertension.

Small aneurysms of the intracranial vessels are developmental - due to a weakness in the vessel wall at certain points. You cannot cause one to develop. I don't see how masturbating while recovering from a concussion can hurt you.