Hi Rosie, Welcome to HealthcareMagic Forum.
It is not related to your anesthetic
effect, since you have had it 4 days ago. But you can take any of the PPIs after consulting your Treating Doctor. It could be drug induced gastritis
as well. Get yourself examined by a Physician.
Drink Plenty of water, If you smoke and drink, Avoid it. Exercise regularly and maintain a Healthy weight.