It actually sounds like you were right and not wrong to insist on a biopsy.
Usually it is quite easy to tell the difference with the erythematotelangiectatic type of Rosacea. This is the type in which there is a sheet of redness spread across the center of the face, often times with small blood vessels called telangiectasias.A basal cell carcinoma will appear as a pearly, shiny papule or nodule oftentimes with a telangiectasia ( wiry thin blood vessel) perched on its top or emanating from the side. Since this is the type of Rosacea usually found in females, there is not much of a diagnostic challenge.
However, if you have the papulopustular variant, in which there are large pores, knobby bumps, and intermittent pustules, this can be more difficult than it would first appear. The granulomatous type of Rosacea ( roughly a bump from a cluster of lymphocytes, a type of white cell) can be even more of a diagnostic dilemma. Usually a basal cell is a bit more shiny. Growth in a bump would also be indicative of a basal cell. Any sort of ulceration ( hole formation) is an ominous sign.
However, even the most experienced dermatologist may be forced to biopsy one of these lesions to rule out a basal cell.
The fact that you have had two of these lesions, requiring Moh's chemosurgery, will emphasize to all of your physicians, not only your dermatologist, to be en garde.