Phal white spots. What are these? Please help! :)

[JJsage]

Hi everyone! I'm new posting here but I browse a lot. I'm hoping someone can help me out. This sweet lil phal started growing a new leaf. It's almost done actually but it definitely halted. Idk if these white spots that I found today on the underside of just one leaf have anything to do with it. What do you reckon these white spots may be? In real life they look kinda like grains of sugar. Thank you in advance for any help!