I Had A Tooth Extracted, Lower Molar, Surgeon Said Tissue

I had a tooth extracted, lower molar, surgeon said tissue was inflamed and put me on antibiotics. I believe the infection spread to my head and neck, but is better today. The day after the surgery I felt like I had the flu, that was two days ago, I'm feeling better today. What should I watch for and when should I see a doctor? I don't want it to turn septic. No fever.