3 days after cheeks done with Juvederm plus with cannula. Burning sensation can't smile, left with black bruising and look weird

Thank you for your question. Swelling and bruising are common side effects of dermal fillers to facial areas and can last approx. 2 weeks. Reassess after 2 weeks and schedule a follow up with your injector to discuss any further concerns. Best, 

Without photographs, it is difficult to determine the source of your problems. It sounds as if you may have significant bruising and should be evaluated promptly by your injector.

The problem with the general public's perception of fillers is that they are a commodity and just search for the best price. This is not the case. The most important factor in choosing who to go to should be experience and results. Even if cannulas are used, bruising can occur, bit not usually to the extent you describe. Also it sounds like placement of the filler might not be correct. I'd wait for about a week and then get reevaluated.