Hi and welcome to the forum
The frog is red around the face and on the back legs. Has it been injured?
There are very few medications that can be used on amphibians, Methylene Blue and Triple Sulpha (Tri Sulfa) have been used and sometimes work. Most fish medications will kill frogs. Diseases are one of the reasons frogs and fish should not be kept together.
Dropsy normally causes fish to bloat up overnight, do a stringy white poop and stop eating. If the frog is still eating and doing normal poop, that is a good sign. If the frog stops eating, that is a bad sign.
It might have air in its intestine or it could have fluid in its abdomen. Air will usually cause the frog to float up. Fluid normally causes them to sink.
It might be developing eggs, however that normally causes them to get fat over a few weeks, not a few days.
Tumours and cysts normally take months to make them that fat.
Check the water quality for ammonia, nitrite, nitrate and pH.
Do a big (75%) water change and gravel clean the substrate every day for a week. the clean water might help the frog fight off any infection around the head and jaw. You might need some sort of antibacterial medication like Methylene Blue or Triple Sulpha, but check with a frog specialist first.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.
Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.
Contact a zoo or herpetology department and see if they have any ideas, or check online for a frog forum. If it was a fish, I would have more info for you but I only know the basics on frogs.