Doctor called said new spot on latest ct scan

Hi all. I havent posted much on here but put my email address out there and have correspondence with some of you who had questions about your upcoming jaw replacement surgery. I had mine june 2011. All my ct scans every 3 months since surgery have been clear until last friday. My surgeon at md anderson says i have a new spot that is either infection, ive had cellulitis on face twice, or its a new tumor. I have a pet scan scheduled for tuesdayand the doc is hoping it will show clearer whether its an infection or tumor. She will then decide about another biopsy however whatever it is its under he facial muscle and not esily assesable for a biopsy. Ok i guess my question is any thoughts out here on a pet scan being able to differentiate between an infection or tumor? Also ive had the cellulitis since june 15, 2012. My scar under chin has been red constantly since june 15. They put me on antibiotics twice, pain in jaw went away but now the spoy on ct scan is right where the pain was. Ive had total lack of energy, i mean its almost too much work to breathe, so unlike me. But that can also be a sign of infection not jyst cancer, right?