The infection rate of 0.08% in the current study was lower than infection rates observed after permanent implants (13–15). Prophylactic antibiotics were not used before injection of Macrolane. There were two cases of suspected infection that improved after a course of intravenous antibiotics, while a third woman with symptoms of infection required more extensive treatment. This woman received 30 mL of Macrolane in each breast, followed by an additional 30 mL seven days later. Redness and swelling of the left breast, which was monitored by the woman at home, were evident 10 days after the second injection. Twenty-six days after the second injection, the woman presented to the clinic with a temperature of 38°C and had difficulty raising her left arm. These symptoms improved after intravenous antibiotics; however, after a few days, redness and swelling of the right breast appeared. Two weeks later, the woman was admitted because symptoms did not improve. The entire right breast was red and swollen (Figure 1A); therefore, a large volume of hyaluronic acid and pus was aspirated from the breast. Wound irrigation was performed (Penrose drain) and an additional round of intravenous antibiotics administered for four days. The patient had a white blood cell count of 8.6×109/L, a C-reactive protein level of 21 mg/L and bacterial cultures of the drained material showed methicillin-sensitive Staphylococcus aureus. The patient underwent an additional five days of antibiotics and the drain was removed on day 10. After treatment of the infection, there was a difference in the appearance of each breast due to the removal of the hyaluronic acid from the right breast

Surgeons should make sure that Macrolane is injected under aseptic conditions to ensure sterility

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4173863/

So her complications may be caused by unhygienic procedure 

edit- this study and the above case are not related, just a similar case