Hello and welcome to HCM.
Sorry to know about the incident.
Corrosive substances in harpic cause such ulcers in stomach and oesophagus.Though acute phase of injury is treated in such way so as to minimize the impact of chemicals,there are still chances of strictures or narrowing of oesophagus getting developed in 3-4 weeks.
If I were your treating doctor,I recommend,
-Take small meals.Include more of
liquid diet.
-Avoid caffeine and spicy,hot,fatty food
-Combination of
proton pump inhibitor and antimetics like
omeprazole domperidone needs to be given.Steroids may be necessary.(prescription drug)
-Visit to gastroenterologist is necessary.The further assessment requires
endoscopy,radiological studies and planning of surgical interventions if required.
Hope this information helps.
Wish her speedy recovery.
Thanks and regards.