I purchased a very tall (8 ft) and healthy corn plant a few months ago and have been doing my best to provide it with the right growing conditions. It's in a bright room but never receives direct sunlight, the temperature is kept between 55-75, and I water it regularly, but let it dry out before rewatering. Unfortunately, I believe I may have also been too attentive, in that I decided to fertilize and repot as well. The reason I decided to repot was that after fertilization, roots started growing straight up out of the pot, so I assumed it was root bound and needed more space. Anyway, now I have many mottled leaves with various yellow, brown, or semi-transparent spots (sort of like a frosted window where that part of the leaf is thinner than the rest) and I'm worried that the situation is getting worse, as it's appearing on new growth. Does anyone have any recommendations as to how I can save my Dracaena?