How bad is osteomyelitis in a teenager? Do they get full recovery or not?

Serious. Osteomyelitis is a bacterial infection in the bone. This infection requires 4 to 6 weeks (or more) of intravenous antibiotics. In some cases, surgery is required for complete healing. In most cases, with early recognition and appropriate therapy, a complete recovery can be expected.
BAD. Osteomyelitis is bad, regardless of age. Aggressive treatment with antibiotics and/or surgery can result in a successful outcome. Dr. Latva.
Osteomyelitis. It is a difficult infection to treat requiring anywhere from 6 to 8 weeks of intravenous antibiotics and sometimes surgical debridement. It is certainly curable, but the type and location of bone determines the course.