I agree looks like dropsy to me... :(
Dropsy is usually caused by poor water quality, or could have been transferred from another fish, or something that was in the water of an infected fish. Dropsy is more of a symtom of internal parasites.
Did you get any new live plants or snails recently?
•Symptoms: Your betta will have a bloated belly and raised scales. They will look like a pine cone. This is usually a fatal disease caused by an internal bacterial infection resulting in internal organ failure but many have had success bringing fish back when treated quickly.
Early Symptoms: Swollen eyes (important), Gray belly (important), Clamped fins, Lethargy. If your fish has swollen eyes and a gray belly, I suggest that you treat it for Dropsy.
•Treatment: If you spot the early signs of Dropsy then treat him/her with ES at 1-2tsp/gal and Jungle’s Anti-Parasite pellets while performing 100% daily water changes. It helps to increase the temperature to 84*F. If he/she has begun Pineconning then do the full course as described below:
Performing daily 100% water changes. Increase the temperature to 84*F. Add 1-2 tsp/gal Epsom Salt. Use API General Cure OR API Erythromycin OR Maracyn II and/or Maracyn for best results. Feed something containing Metronidazole, for example, Jungle’s Anti-Parasite pellets. If caught early, Dropsy is curable.
You can't treat snails because the salt or medication will kill them... The snails don't get dropsy themselves, just transfer it.
I would treat ALL of your girls, any bettas exposed to her or any tank equiptment can be infected.
Wash everything with vinegar and hot water, change all of the sorority tank water...