I persoanally haven't has good results using cuttings from between nodes like that, but that's me. If she doesn't show some leaf soon, she doesn't have a great chance. Your roots didn't or haven't continued growing for whatever reason. It's all about the roots!!!!! Have you ever seen the rootball on an 18" hydro gro? It's literally 14-18" long and 6" on dia. Looks like a wad of blonde hair, sortof.
Soil ph is cool?
NOT overwatering?
Big thing I've foud along the way is not to feed them anything whatsoever until they have some good new growth green on them, which means they have roots, and can begin to metabolize the food. Until then, it'll burn the piss out of them. The more nute sensitive hazes and sativas will turn into a little pile of cooked spinach if you hit them with anything stronger that water.
In the past, if they had a little root when I planted but looked weak or couldn't catch up with the others, I use only ph'd water- (1gal.) w/ 1 or 2 drops of Superthrive, and 2 or 3 DROPS ONLY of BLOOM fert, - for the potassium- and try to get the roots stimulated, It's all about the roots.
Hope your little one feels better, Bro!