Could you get osteomyelitis twice?

Yes. May get recurrent osteomyelitis in same location if not treated thoroughly. May get osteomyelitis at different site. Multifocal osteo. Can occur simultaneously in multiple locations. MRSA osteomyelitis has tendency to be multifocal. CRMO, chronic recurrent multifocal osteomyeltis can affect 2 to 11 or more sites. Not necessarily at same time not caused by bacteria. Autoimmune process treated with NSAIDs.
Yes osteomyelitis. Osteomyelitis is difficult to eradicate and often can "reappear" even after years. But certainly it can occur more than once.