As others have stated, diving with fluid in the middle ear can cause pain and damage to your ear...don't do it. You could contact DAN. Probably the best that DAN will do is refer you to a different ENT who is familiar with caring for divers. When it comes to ears (and pretty much any other medical condition), there's no substitute for a proper physical exam. I think we can assume that your ENT knows how to use an otoscope and made the correct diagnosis.
It sounds like your ENT is erring on the side of under-treatment. Did your ENT give you the option of treatment with some sort of corticosteroid? For your condition (presumably barotitis media - Type I or II), sometimes ENTs will prescribe a systemic corticosteroid +/- nasal spray corticosteroid + systemic or topical nasal decongestant (Afrin) +/- antihistamine (if nasal allergy was pre-existing). If there's purulent discharge from the nose or cough productive of purulent sputum, then a systemic antibiotic should be added to the mix since secondary middle ear infection is likely. Type II middle ear barotrauma usually resolves in 3 - 14 days. The standard recommendation is no diving until otoscopic exam shows complete resolution and the patient is able to autoinflate both ears at the surface. Is it possible to get in touch with your ENT again to inquire about this?
In the future, don't wait for ear pain to remind you to equalize. As you gain experience, you'll learn to equalize early and often. That's probably the best way to prevent barotitis media.
Also, for future dive expeditions, consider purchasing trip insurance. Weird stuff happens. I think we all get very paranoid before a warm water trip with respect to getting sick or injured. It's never a good idea to test out an ailment/medical condition at a remote dive destination with limited access to health care. Diving is a physically demanding sport that places the body under unusual stress. Don't mess around with it.
Get well soon...