As it's an uncomfortable subject perhaps doctors don't talk about it much with patients, but post-TBI sexual disinhibition is not uncommon.

There are good discussions of this issue in both neuropsychologist Dr. Glen Johnson's book, Traumatic Brain Injury Survival Guide and in the sometimes off colour, TBI HELL: A Traumatic Brain Injury Really Sucks by George Gosling.

If your hyper sexuality is confined to dreams, I guess that's fortunate. In fact, dreams, even really bad ones, are a good sign for TBI patients. Those with really significant injuries sometimes lose that capacity.