I agree with Doc. The usual side effects from this type of concussion include: headaches, difficulty concentrating, vertigo and lightheadedness. In most people, these resolve in about four to six weeks. The biggest concern I would have about diving after a concussion is the concentration issue. I have treated many people with complex jobs (surgeons, lawyers, pilots) who, after a concussion, looked, felt and acted normally but could not focus their attention long enough to do their jobs for up to several months. I suspect that's why many quarterbacks who have concussions don't return to the game for weeks or months --- not just the fear of re-injury, but the lack of focus and difficulty with remembering plays and reading defenses. You need to be able to read your computer and gauges (and remember to do so underwater), navigate, and do other cognitive skills when diving. Until it is certain that you have not any cognitive short-term problems, it's best to stay out of the water.
I second the opinion of seeing either a neurologist or a neurosurgeon in follow up before diving. Unless you have prolonged vertigo or dizziness, an ENT evaluation is not necessary.