Yes if it is lympho, maintaining prestine water quality is important, and it should resolve on its own. It could also help to up the feeding schedule/quality and maybe add some vitamins.
Lympho can absolutely appear on the fins. in fact this states it usually starts there
Lymphocystis What You Need To Know: * This is a virus that many fish carry for life. The white nodules (cauliflower-like growths) can grow both externally and internally; so symptoms are not always visible. * There is no known cure for Lympho. However, feeding vitamin-enriched foods and...
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Again, I don't want to insist it isnt ich. But given your set of circumstances, it would be worth considering. The lymph spots wont change location.