I have been going to my dentist for ortho care: 6 month smile braces. This weekend I have been having on/off pain on my left jaw. I visited my dentist and she wants to inject my with Arestin, local antibiotic. My pain is not localized. She would not prescribe an oral antibiotic. I have Keflex at home, can I start using it? Arestin is for bacterial infection, but I feel I need a general antibiotic, not a localized one that is very expensive, and not covered by by insurance. She wants to start doing 2 at a time. Please, guide me.