After-effects of root canal for abscessed tooth

I am in the midst of phase I of a reconstruction of my teeth due to bruxism and/or  TMJ. After the 4 hr. appt to prepare my upper teeth for the impressions, my dentist decided to fix a problematic tooth not specified in the phase I project. He found I needed a root canal, which he did. During the procedure, he said my "devital" tooth had abscessed and he worked on that. I was on antibiotics (augmentin) before the surgery, which I continued due to the abscess but the day following the root canal, my face is very swollen, from the nose to below the jaw bone and slightly pink.  It is not hard and not terribly sensitive today.  What could have happened to cause this swelling and do you think the abscess has not been completely resolved? I do have a follow up in 3 days, but am very anxious about what may have happened, especially since the swelling goes below my jaw and the tooth worked was an upper one...

[scottma]

Flare -up may happen after canal instrumentation. Systemic administration of antibiotics can generally clear up facial swelling in 3 days. If not, it's probably because of drug resistence of infected bateria or compromised host immune system. Swithching to another antibiotics may be indicated if infection does not subside 3 days later.