I agree with Austin.
Lymphocystis commonly manifests in angels and butterfly fish (other species too!), that have been held in copper. This is the fish equivalent of "the cold". Not overly concerning in its own right, but does indicate underlying immunosuppression.
As Austin suggested, best to get this fish out of medication ASAP and start rebuilding the immune system. Live foods, fresh greens, probiotics and B12 will all help your fish recover and live and long, healthy life!