I have terrible sinuses. I get frequent infections, particularly in tr maxillary sinuses. However, I had a filling in one of my top, back left teeth Thursday. I already had sore throat when I went in. My throat has become increasingly painful and over the course of today (Friday) I notice a marble size lump on the roof of my mouth toward my top right furthest back molar. The prompt care dr said it is an abscess and sent me to the ER, BUT I called the dentist on call before going to the ER and she told me NOT to go to ER and gave me Amoxicillin 500mg TIDx7d. How can I tell I it's dental or sinus related??