Cervicofacial odontogenic infections can have an aggressive evolution with life-threatening complications. Management in many cases can be a challenge for clinicians, implying an extra focus on individual inflammatory parameters. The aim of this study is to evaluate the evolution of inflammatory markers for the included diagnosed odontogenic cervicofacial phlegmon cases at the moment of hospitalization and after receiving surgical and pharmaceutical treatment. Materials and methods: A total of 39 patients diagnosed with odontogenic cervicofacial phlegmons that were admitted to the Maxillofacial Surgery Department of the Emergency Hospital from Timisoara were included in the study. The main focus was the parameters represented by the systemic immune-inflammatory index (SII) based on neutrophil, platelet, and lymphocytes count; the neutrophil–lymphocyte ratio (NLR); C-reactive protein level (CRP); and white blood cell count (WBC) before and after the treatment as potential prognosis factors. Results: The results of the study after analyzing the included parameters revealed a significant difference between the calculated values of the SII, NLR, CRP, and WBC at admission and at time of discharge, being directly influenced by the treatment. Conclusions: SII, NLR, CRP, and WBC dynamic changes in severe cervicofacial odontogenic infections can be influenced by receiving accurate surgical and pharmacological treatment, with the potential to become future severity prognosis indexes.