Complication following Profhilo treatment

Patient description

Caucasian female, age 38, previous toxin and Profhilo with no complications. No other fillers or injectables in the past. Fit and well. No recent dental visits. 

Case description

I am presenting this case on behalf of a colleague:  Uneventful treatment with toxin to upper third face, and 10 BAPS Profhilo administered in regular Profhilo protocol positions. Days 1-4---- no problems. On day 5 she contacted the clinic with mild swelling, redness and heat affecting upper and lower lateral lip on  one side only. No pain, no tenderness, no vesicles, no fever. See photo with green circle. Differential diagnosis, vascular occlusion, vascular spasm, (although timing and distribution and appearance don't really fit), oedema from spread of Profhilo ( why limited to  small area only?), infection. My colleague decided to try Topilase ( topical Hyaluronidase) and it had an immediate effect reducing the swelling. The patient was sent home with instructions to continue with the topilase. The outer lip settled mostly  (mild swelling on the outside only) but today ( day 7) the inner mucosa is now red. Given the spreading redness and warmth she has been started on antibiotics today. The response to Topilase would appear to support a diagnosis of vascular origin, but if so what is the mechanism? Could this be something entirely unrelated to her Profhilo treatment? I would be very grateful for any views and comments from the forum. Thank you very much.