It’s a bit difficult to tell from the photo, but it could certainly be a fingerprint/veil. I’m not sure what kind of doctor you are, but do you have access to an optometrist’s/ophthalmologist’s slit lamp? I’m an optometrist, and I use my slit lamp like a binocular gem microscope. Most slit lamps allow magnification from about 10x to 40x.
I’m not sure how small/large the stones are on this piece of jewelry, but it is certainly possible that these are all natural stones–unheated is less likely, but also certainly possible.