Did you become unconscious (even if it was for seconds) when you fell? If yes, the chance is that there was a injury
to your brain which may not always be picked up on CT scan
. With time the minor injuries heal and nerves which were destroyed reconnect. You definitely will not need to take it forever. However since medication is helping so you can continue it as long as it is needed. It may take sometimes few months to come back to normalcy.