Thank you so much, DDM. It's eased off again, but the fact that it started again says the fragment is probably quite small and often dormant. It surprised the heck out of me, leaving me wondering if there was any way to reach it and get rid of it by this time. Hope surgical removal isn't needed. I still have the slight discoloration in the area right next to the part that recently acted up. Coral can be incredibly persistent!
Lois,
If you are having repeated flareups of this over time, you definitely need to be seen. If you're ever at a point where your immune system is compromised, the infection could spread. A GP should be able to remove it in the office if it's just a superficial fragment.
Best,
DDM