Swelling on cheek & Gum

Hello Doctor,

I had pus coming out from my one of the gum 6 months ago, I went to dentist he removed the plaque clean teeth.This stopped pus.
Now just before 10 days i got that same gum swollen & became red. suddenly swelling shifted towards my still there was no pain in tooth or gum. except the pain in gum when pressed. Again i went to dentist he took Xray & sugested another surgeon to extract the tooth. But surgeon was not able to answer if the swelling is because of tooth why it is not paining. he suggested to get opinion of ENT specialist.
Then i went to another dentist. She told me swelling is definitely because of tooth & tooth is dead due to infection so there is no pain. she just completed Root canal treatment yesterday. but still there is a swelling on cheek, due to which my left eye is not opening completely. I'm taking Cifran-oz & Clamp-625 doing salt added warm water gargles, applying ice on swollen cheek.She told me it will take time for swelling to go. One strange thing is that as day progress swelling reduces & when i wake up swelling is same as earlier day morning.
Why swelling is taking so much time to go?
Is the swelling is really because of tooth only?
Or shall i consult ENT?