hello sir, obviously diagnosis is OSMF and 3 finger mouth opening is quit ok but it can worsen, left ear pain either due to oral physiotherapy or separate joint problem which clinically & radio graphically has to be assessed.
Burning cheek can be solved is a sign of OSMF only.
Mouth opening if still reducing may require fibrotomy by oral surgeon.
Next Steps
Avoid all oral bad habits, oral physiotherapy and regular checkup