Thanks for sharing your concern.
Your history requires little more clarity, you have mentioned that you got root canal treatment
done. This is done to treat a tooth which has involved the pulp and periapical area.
It is not done for gum swelling. The cause for your gum swelling is the abscess, which was due to infected tooth.
has injected local anesthetic
to relieve pain during root canal treatment procedure.
Its effect last for few hours only, this will not lead to sinusitis
Please mention which tooth are you talking about ? is it your upper left side first molar?
Here i would like to mention that if this is the tooth on which RCT has been done, then in rare chances it can lead to oro antral fistula. The white patch
and mucus thicker than usual could be the result of this.
For this i would suggest you to revisit your dentist for clinical evaluation. Have you mentioned to your dentist about your recent sinusitis and the antibiotics that you were taking prior to dental treatment?
Your pain underneath your ear on right side is not related to this.
It could be due to impacted tooth
in the lower jaw or a periapical infection on right side , for this you must get an xray done to rule out any impaction
or infection. .
Hope i have answered your query.