Is this bruised cheek from root canal?

Hard to say: Bruising can occur after any dental procedure that requires an injection. If the needle nicks a blood vessel, a bruise can result. Bruising after a root canal procedure can also occur if cleansing solutions are expressed through the end of the tooth. These are complications that can be quite serious. If your root canal was recent, call your dentist and ask to be evaluated.

I don't think so: If your bruise is related to a root canal because of extrusion of fluids you would probably be at the er now. Bruises may be related to any dental procedure, related to the injection , especially after surgery. You should go back to your dentist for check-up anyways.

Can be related: Likely from the anesthesia. If not resolving, see the Dentist.

Not very common: The bruising of the skin/cheek or under the jaw line may occur occasionally, after root canal therapy. If concerned, see your dentist for post-op appointment.