What is Happening to My Lens?

Ray UK wrote:

I very much doubt that you have damaged the coating, it is much tougher than people believe, often it is harder than the glass underneath it.

No, coatings are never tougher than optical glass. Amorphis solids are bound to be much more robust than atomically thin layers of combinations of precious metals (solid at room temp) and other elements (e.g. fluorine, gas at room temp). Both the thinness and significant composition by mass of gasses makes coatings relatively fragile. they only have perceived durability because they sit atop a quite strong substrate.

I have never used Pancro lens cleaner but I expect it is just a soap solution in purified water like most cheap lens cleaners.

Not so, isopropyl alcohol or acetone. Soap would leave a residue.

I think you have just dispersed the sunscreen and spread it over the surface, if it is an oil based sunscreen then you need isopropol to clean it off which will actually dissolve the oil. Apply the isopropol to a soft tissue, wipe the lens and discard the tissue, repeat as necessary with a fresh tissue each time until all trace of the oil has gone. finally clean the lens with a tissue and lens cleaner. Do not at any time drip any fluid directly onto the lens surface.

You can drip IPA on optics all you want. Most of them are ultrasonic cleaned by submersion in an agitated solution of it anyway.

You shouldn't* use cheap IPA or acetone (e.g. nail polish remover, paint thinner) as they are low purity, e.g. 96% in some cases. If the impurities are particulate matter, the forced streaking of them across the surface is all but guaranteed to damage the coatings. Using lab or reagent grade (99.8, 99.9% purity) hedges your bets on that.

Some may find this advise to be overly cautious, but a small quantity of "proper" chemicals is a much cheaper investment than a ruined front group. 1L of 99.5% acetone with the remaining impurities guaranteed to be water is $44 from Sigma-Aldrich, which is ~2x cost over something like a bottle of nail polish remover.

e: you should also use lab tissues, e.g. kimtech wipes.  Facial tissues, e.g. kleanex, puffs, contain oils and other compounds designed to sooth the skin that you do not want to streak on your lenses.  Lab tissues are only a suitable type of paper, and designed to lint less.  Lab tissues are cheaply available, even sold by Amazon.