Teething and diarrhoea are not directly related. It happens only because the baby puts anything in mouth. The treatment started by your doc is correct. Loose motions will take some time to resolve even after the antibiotic course as it takes time for the intestine to heal completely from within. Keep your child well hydrated till the motions are well formed to avoid dehydration
Health Tips
Good intake of oral fluids, Apple, pomegranate juices, banana, rice kanji, sago grain kanji, are helpful