...and then t'was gone! Strangely that unexplained swelling did go down 24hrs later. I somehow sensed that it would. I contacted Dr. Umar who is closely observing the behaviour and he suggested the optional use of hydrocortisone 1% applied twice daily. Before I could get to that email and purchase the hydrocortisone, I had already applied a light amount of Videne (as a one off) to keep it clean and by the morning all seemed well. There appears to be a slight red scab as if it had been grazed, but absolutely no swelling. Overall, consistent progress.
See below for the pictures taken - The slight tannish colour above and below the scar is the Videne: