Based on the information provided, I have no clue. We generally like to start with water quality numbers as so many issues are related to the water quality. If you can, please provide numbers for ammonia, nitrite, high range pH, KH, pond temperature, and any behavioral issues, like flashing, breaching, isolation, etc. Maybe, we will see something that will help.
I have never lanced a lump, so the fluid is something that I am not familiar with. That reddened area does not particularly look like it is infection, though it could be a subsurface infection showing through. I have seen shusui with areas of more intense color which would be pattern, but except for some environmental issues I have not seen it come up later.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard