"Chronic venous insufficiency (
CVI) is a medical condition in which blood pools in the
veins, straining the walls of the vein.
[1] The most common cause of CVI is superficial
venous reflux which is a treatable condition.
[2] As functional venous valves are required to provide for efficient blood return from the lower extremities, this condition typically affects the legs. If the impaired vein function causes significant symptoms, such as swelling and
ulcer formation, it is referred to as
chronic venous disease.
[3]" -Wikipedia
So the protagonist misdiagnosis and prescription of B1 Vitamins may provide some relief, it is a paliative, masking the sympthoms leaving the real problem untreated, it may alleviate the fatigue on her legs but the main issue still there.
The rotting part of it may be due to how when a limb stops receiving blood the limb starts to suffer of necrosis (Tissue Death).
I wonder if the protagonost decision here will end up getting Aina's Mother killed later on.