TMJ is a reasonable diagnosis, but my concern is that TMJ is usually not an acute event.
It sounds more likely that you have eustachian tube dysfunction, and that you may have TMJ as well.
Tinnitus is not really something that is common with TMJ.
If I were you, and if you have not done this already, I think it would be very reasonable to get in with an ENT doctor (otolaryngologist) prior to your departure.
The advil is reasonable, but with your inability to clear your ear I am concerned about air travel as you may be 'squeeze' in your middle ear with the altitude change. Usually, people with eustachian tube dysfunction are placed on degongestants for a short time to help the ear clear. An ENT would also have things he could do in the office to alleviate the blocked eustachian tube.
The 'wild card' here is the tinnitus. Again, a specialist would be better equipped to get you better before your travel and I recommend this as your next step.
You might go to your local pharmacy and get some Afrin nasal spray and some Mucinex. Both are over the counter and the pharmacist can direct you as to their proper use.
I am standing by if you have any questions for me. If this has answered your question then positive feedback is always appreciated.