I would go with Abrahm on this one.
I had a client once who is a avid reptile keeper and suddenly decided to keep axolotls. He tried experimenting with different types of light, assuming (wrongly) that axolotls would have similar requirements as reptiles.
He used black light bulbs as a light source and had it on for half a day at least (12 hours?). In addition, he didn't really have a shaded hiding spot (he used those clear plastic hamster cubes). He had a white albino axie which presented with cloudy and ulcerated cornea and really severe skin shedding. I would have to say there might be a combination of other causes (poor water quality etc), but the extended and prolonged use of the black light bulbs are highly suspicious.
Most aquatics/exotics vet in Australia would recommend just the use of ordinary aquarium lights or fluorescent lights switched on for only up to 6 hours per day (can be automated). There should always be plenty of shaded hiding spots (pipes, logs, caves etc). Things like a transparent jug although pretty and offer some 'hiding' capacity, doesn't fulfill the need for shade and shelter. There is a school of thought that some limited aquarium light (very low UV) exposure can still be beneficial to the axie, although much more research is definitely warranted in this area. The hypotheses are to help regulate biorhythmns (breeding, sexual maturity, hormonal levels) and certain metabolic pathways.
Cheers.