I have to laugh when I see my homemade mahl stick in one of these photos. Hey! It does the job, and its large size is useful on large paintings.
Two Cakes hit a wall. Sometimes I get blind and can no longer ‘see’ the painting. I’ve learned from experience that that is usually related to the drawing. Something bothers me and it can take time before I put my finger on it. In this case, I am refining some of the drawing (white chalk marks on the surface).
Has this happened to you? Have you gone blind regarding a painting. If so, loop back to the drawing. When it happens to me, I will sometimes rework colors or tones but usually, like I said, it goes back to the drawing.