Platy with torn mouth or fungus?

[Nawirl]

I’ve had this platy since a fry in August. This morning her mouth is protruding. After hours of trying to get detailed photos or videos, I still can’t tell. There are no signs of ich on her or other fish. No fuzzy or white spots on mouth. She seems to be eating and picking at plants like normal. It’s like it’s swollen or torn. But is there a black fungus?
55 gallon tank
25-30% water changes every 7-10 days.
platys, guppies, cherry barbs, corys, dwarf gourami, otocinclus
sand substrate, live and plastic plants
Water parameters within normal limits. Feed flake, algae wafers, freeze dried blood worms, bug bites

 

[BigManAquatics]

Can't really tell. Some of the photos make me think that mouth got a bit mangled up on something, though.

 

[Nawirl]

So other platy now showing white lips. Isn’t mangled like the first platy. I’m using melafix and Pimafix for 6 days now. 2nd platy just started showing signs yesterday. It seems like since they’ve been in the tank with the other fish, they are all susceptible. Wouldn’t treating them all be better than QT? Other posts recommend kanaplex and furan-2 or a major antibiotic. It’s so confusing. If I do ciprofloxacin or trimethorpine how do I get that for fish? Do I need a prescription?