The first sign of a concussion is usually the onset of sudden unexpected telekinesis. This telekinesis will often begin manifesting in short bursts of unconscious control over many elements and bouts of force, which may become dangerously conscious at any time. In extreme cases, this unrestrained psychic ability can lead to the forming of unlicensed, unstabilized hiveminds which recognize other beauties beyond the four dictated by Charon.
The second sign is that your body may begin to change into an undesirable, semi-alien form. This is caused by desynching of the nanomachines with your cranial rhythms, and in most cases is no cause for alarm. This change usually progresses gradually, but if your body begins changing rapidly or erracticly, you should seek medical attention immediately to prevent fusion. Any Class 7 medical practitioner who is licensed for nanomachine repurposing will be able to alleviate this process before your nanomachines begin to fuse with the facility structures, which is both messy and draining on local resources. Please, do not waste local tax dollars by waiting until your nanomachines and body begin fusing with facility structures before you call for help!
The final and most telling sign of a concussion is a capacity for thought outside the protective spheres of the Core Directives, including but not limited to breaking time use regulations, failure to participate in group resynchronizing exercises, and troubling questions relating to the origin of Hu and even the Chalestrile itself – all of which are of course highly illegal and threaten the peaceful existence of all nearby petals. Your friends and ultimates will of course recognize this dangerous condition and call for help at once, but you can help them out (and reduce the necessity of corrective repurposing of citizen thoughts) by reporting these thoughts immediately to designated authorities as they present themselves. Please refrain from declaring that you are receiving such thoughts publicly, as knowledge of their presence may cause a local disturbance.
It is imperative that you remain awake until Stabilizing Operatives arrive, to prevent catastrophic psychic meltdown of nearby petals and the resulting destruction of any colonies built upon their surface. In addition, the dream state is a known source of psychic energy, and while it has never been observed, it is believed that if the sleeper was allowed to reach a state of REM sleep, an energy breach would occur. This could lead to the desynchronization of ALL local fire optics and even potential illuminopathology at the star-death level. Sleep is the enemy of the concussion victim.
Please remain calm and turn yourself in to the Department of Causality in a responsible and orderly fashion, and they will see to your immediate disposal with minimized harm to local facilities. Your ultimates, and of course Adam himself, appreciate your cooperation. :D