Need context really to what the red sweater means to the person but it’s basically saying even when they stop feeling anxious/ ill the “red sweater” (whatever this means on context) still sits there like a big problem. You can infer the red sweater a big problem through the word “mountain” and is something they need to overcome. Red had connotations of “love” or “fire” maybe. Depends on context. Hope that helps :)
