Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency help after a major facial injury if there is heavy bleeding, severe deformity, loss of consciousness, or difficulty breathing or swallowing.
Breathing or swallowing difficulty with rapidly increasing swelling is also an emergency.
Sudden facial weakness, difficulty speaking, or weakness in an arm or leg is not a typical TMD symptom and requires emergency assessment.
Prompt assessment is appropriate if your jaw becomes locked open or closed, you develop notable facial swelling or fever, or symptoms begin after an injury.
Arrange a routine dental or medical assessment if pain lasts for more than a few weeks, keeps returning, or interferes with eating, sleep, work, or school.
You should also seek assessment for repeated locking, steadily reduced movement, or a new change in how your teeth meet.
These problems may need treatment for a dislocation, fracture, infection, or another condition rather than routine TMD care.
Every sign above is quoted from the sofidex article on Temporomandibular (TM) disorders. If you are not sure, err upward — it is always reasonable to be checked.