Single white spot on purple tang

[Toofattofish]

I have a new purple tang that went through a month of qt observation + prazi, without any issues during qt period. For some background I added the fish to dt last week and within 2 days it shows symptoms of lympho on 2 spots. These spots disappeared but the skin was hyperpigmented/black on those 2 areas, but it has never scratched or shown any abnormal symptoms and it eats everything.
Since this morning it now has a new white spot on its torso which I'm not sure if I should be concerned . There was no prior lesion on this area. It looks too big to be ich and not sticking out like typical lympho. Is this anything to be concerned about?
Thank is 120 g reef, up about 2 years
Minimal nitrate/phos
Tankmates are mandarin, azure damsel, clown pair, social wrasse
The others have no signs/symptoms of anything. There's no fighting or aggression.

 

[Humblefish]

Sometimes Lympho nodules grow on the body and can cause a temporary discoloration to the skin/scales after the nodule has dropped off.