Unable to open mouth all the way month for work on back upper tooth. what are my options? need asap.

Varies: If the inability to open is a muscle related problem, moist heat, soft diet and an over the counter anti-inflammatory may help. Sometimes a skeletal muscle relaxant may be prescribed as well. If the inability to open is related to a possible TMJ problem, a more extensive exam may be needed with some additional diagnostic studies. Also, an infected tooth can also limit your ability to open.

See below: Need to determine why you can't open all the way. Is it recent or always been that way. Possibly a bite block to help support your jaw while open. Possibly having work done under sedation - either oral or IV may help. Get a diagnosis of why you have limited opening first and then can evaluate for options.