Having spent 15 years working in cardio-pulmonary medicine at two of Baltimore's largest teaching hospitals, I can unequivocally say that 95-percent of the physicians I've come across in my lifetime are not worth a damned. The vast majority are pill pushers who hope to make enough money to retire early and put their kids through medical school.
When you do come across a knowledgeable physician or surgeon, which is rare, they tend to be the ones that take the time necessary to make a proper diagnosis, and then provide the correct regiment of treatment. The major problem that most individuals have is they have no way of determining whether or not the physician or surgeon they're seeing is competent. Sure, you can look on the Internet and find out if they have some malpractice suits filed against them, but other than that it's next to impossible to do anything more than make a WAG (wild-assed guess).
The best advice I have for sailors is to have a fully stocked first aid kit onboard, one that contains not only the usual array of bandages and aspirins, but additionally, antibiotics, pressure dressings, splints, sutures and needles, and an adequate supply of any prescription drugs you may be taking. In my case, I even have a bottle of nitroglycerin tablets on the boat - just in case I have that third heart attack while anchored in the Dry Torgugas.
You were very fortunate to find a highly qualified physician while visiting Mexico. Most of the better ones tend to head north to the U.S. where the pay scale is much higher. I knew a couple of ex-patriots from south of the border, both of which have since passed away. Both were excellent surgeons and outstanding diagnosticians.