Hard to say from a distance ... but the marking is typical of too much root moisture. Fungus' and virus' are thoughts too far at this stage. Frankly I think that if your plant has survived this far then for sure it will survive.
Assume you have taken it out of the humidity. Don't be afraid to water and feed if yr grow material is well drained. Make sure yr grow material is draining well. Needs plenty of light now ...
Good Luck ...
"Life is ... a Continuum ... with no Beginning and no End. It is not going Somewhere ... it is always Here." Osho
“The whole modern conception of the world is founded on the illusion that the so-called laws of nature are the explanations of natural phenomena.”
“… even when all possible scientific questions had been answered the problems of life would remain completely untouched” (Wittgenstein)