Krita randomly stopped showing my strokes unless I was on a particular layer and was drawing on an area previously marked (like, before it stopped working). I've tried adding new layers, but the only other layer it'll "work" on is the background layer. Can y'all help me out please? I really don't wanna lose my progress. Thank you in advance.

Maybe just consult the manual? For instance, see https://docs.krita.org/en/reference_man ... pha%20lock .