Live-action ‘90s show where a boy hits his head and wakes up in a fantasy world

Question

His bully chases him into a ravine and he falls and hits his head, transporting him to another world where he has adventures with an alternate version of the bully and a girl who also has a real-world version. It intersperses this with scenes of his mother in the real world --where he’s comatose -- dealing with more mundane issues, like should she keep him on life support, the bully’s remorse, etc.

Answer 1

You're probably thinking of The Odyssey (1992-1994).

From Wikipedia:

The Odyssey is a Canadian-produced half-hour adventure-fantasy television series for children, originally broadcast from 1992 to 1994 on CBC Television.

In the series pilot, 11-year-old Jay tries to join a tree-fort club, led by the tough Keith. As per the prearranged agreement, Jay has brought something of value to contribute to the club: a telescope that belonged to his father (who has been missing several years and is presumed dead). Keith double-crosses Jay and takes the telescope, denying him admission into the club. Jay tries to retrieve the telescope with the help of his physically disabled friend Donna, who uses a crutch and a leg brace in order to walk. Jay falls from the tree-fort, striking his head against a rock and lapsing into a coma.

In the coma, Jay finds himself in a fantasy world called Downworld where no one reaches the age of 16. Not having heard of adults, the children here have shaped society in their own ways, forming mostly tribal clans in the form of Clubs, such as the Pool Club and the Library Club. The biggest and most powerful Club is the Tower, a brutal despotic police state run by the oldest kids, with Brad as the absolute ruler because he is 15, and "knows everything". Jay, not knowing how he has got here and aided by his friends Alpha and Flash (who are identical to Donna and Keith), embarks on a journey to return home — a place that he cannot remember. The journey becomes a quest to find his long-lost father, whose name happens to be Brad, who fell overboard from a small boat into a lake while they were on a fishing trip together and has not been seen since.

Meanwhile, Jay's mother and a coma therapist try to get Jay to regain consciousness, with the help of his friends.

The series begins as you described, with a boy being chased by a bully, falling into a ravine, then waking up in another world where he meets alternate versions of the bully and a girl he knew in the real world.

You can view the part where he falls into the ravine at around the 7:28 mark in the video below.