Would i know if i had a brain infection from tooth infec i took augmentin for teeth n now jaw hurts again worried brain infec or sinus infex ?

Brain Infection: Brain infections from rotten teeth are extremely rare and I doubt you would have the wherewithal to be on the internet asking questions if you had a systemic infection that made it to your brain. So no, you don't appear to have a brain infection. But please see a dentist before your tooth infection spreads resulting in a major health risk and possible hospitalization.

Antibiotics: Antibiotics will control spread of dental infection, not affect a cure. When you stop taking them infection will come roaring back. Whoever prescribed the Augmentin should have told you that, or are you dangerously self-medicating? Untreated, or incorrectly treated, infection will spread. You need to see Dentist, Endodontist, or Oral Surgeon ASAP. Please call now.