What is this? Yellow Tang white spot on mouth area

[isomorphic85]

Pic below.... white spot by mouth area ... trying to figure out best way to treat this. Yellow tang is newcomer and is currently in QT for about 2 weeks. Have already treated with prazi for flukes which appears to have cleared up nicely. He's eating well and seems to be fine other then the spot.

 

[Deinonych]

Looks like lymphocystis. As it's viral, there are no treatments. It should be self-limiting provided the fish is healthy otherwise.

 

[isomorphic85]

typical length of time until it's gone?

should i expect it to spread first?