BS”D
1) Depending when this was, there are a lot of unqualified FSU doctors in EY who should not be practicing.
2) The Gerrer Rebbe’s brocho came to be via this doctor. It may not be an example for anyone else. A similar story is told of the Lubavitcher Rebbe ZYA who sent someone to a doctor who was a chossid of his to get an RX for a creme that might as well have been a placebo. It worked and the patient did not need surgery. Would that creme work for anyone else? Not without the brocho. I think I know what it is, and the FDA allows it to be sold only because it was around for so long and is harmless.
3) I have a nuisance skin condition on the backs of my hands. Simple Vaseline works better than any RX I have ever used and I got many RX’s because when I first noticed it I had a very comprehensive insurance plan. Had I not asked a rov whether I can use hand creme on Pesach and gotten a “no” answer with a recommendation of Vaseline, I would never have tried Vaseline.