Thanks for your query. I have gone through your query. The red spots on the palate can be a herpetic or aphthous ulcer secondary to stress or medications. The altered taste can be because of the antibiotics. Nothing to be panic, consult a oral physician and get it evaluated. Mean while you can take topical anesthetic like lignocaine and topical analgesic like choline salicylate. Once you stop the medication the taste should return back to normal in 10days. Do saline gargling. I hope my answer will help you. Take care.