A mandiblectomy is a heavy duty surgery not surprised you're in pain. I imagine unless you are out cold it will still hurt some despite the meds you're on. That said I would make them aware of your pain. Not all medications work the same for all people a oxy puts me to sleep morphine goves me weird dreams - neither kill my pain, meanwhile 85% of the planet LOVES oxy... Go figure. They could try and find something that works better for you. hugs! And fingers crossed your path is clear of bad news.