Hi.. Thanks for the query.. It seems that you are suffering from the side effects of medicines and antibiotics like Penicillin and even at times painkillers can also cause stomach upset, hyperacidity and other side effects.. I would suggest you to start taking Proton pump inhibitor like Pantoprazole or Omeprazole empty stomach in the morning and antacids like Milk of Magnesia before meals for preventing the symptoms you are experiencing.. You can take Ondensarton if you have nausea and vomiting.. Take light diet and avoid spicy foods.. Take more of Yoghurt in diet as it helps in replenishing good bacteria of intestines.. In case if still there is no improvement consult your treating dentist and get evaluated... Hope this helps.. Regards..