Might concussions cause memory loss?

Memory loss. Concussion causes 2 types of amnesia. Retrograde amnesia means a loss if information from the injury back in time. The most likely loss is recently learned info. You may get the info back. A prograde amnesia is amnesia from the injury forward in time. You are not laying down new memory traces at that time. It is unlikely you will regain memory loss from prograde amnesia.
Yes. Yes they can depending on intensity of impact and how many times the brain got injured.