Haemophilus influenzae is a rare cause of necrotizing fasciitis with only a few previously reported cases. We describe the case of a 44-year-old man who had necrotizing fasciitis of the right lower extremity develop after intramuscular injections of paracetamol on his right buttock. The causative organism isolated was Haemophilus influenzae serotype b. This unusual infection was treated with repeated débridement and culture-guided antibiotics. There was no recurrence of infection at last followup 1 year after the initial surgery. Wound coverage was achieved with the use of a full-thickness skin graft after application of platelet-rich plasma and a dermal regeneration template. This resulted in a cosmetically acceptable appearance of the involved extremity for our patient.