What's up with the egg spot?

[CLCDiver]

What size is your tank? 5 gall
What temperature is your tank? ~80 F
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? There is another female betta sharing the tank, but they are separated.

Food
What type of food do you feed your betta fish? Mini-pellets
How often do you feed your betta fish? once or twice a day with a fast day

Maintenance
How often do you perform a water change? Once a week
What percentage of the water do you change when you perform a water change? 50%
What type of additives do you add to the water when you perform a water change? API Water Conditioner

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? Where the egg spot was there is now an engorged red lump
How has your betta fish's behavior changed? Not at all, she is still active and hungry
When did you start noticing the symptoms? Yesterday
Have you started treating your fish? If so, how? No
Does your fish have any history of being ill? No
How old is your fish (approximately)? A month or two, maybe.

Yesterday I notice one of my new females in quarantine has a red bump where her egg spot should be. When I woke up today, it was even more engorged. It does not look like it pains her, because she'll still rest on the gravel substrate, or swim along the bottom with it occasionally bumping the gravel. And she's active in exploring the tank and so on. What could it be?

[CLCDiver]

Update with a better image and to add that I now think that the swelling is actually a little bit in front of the egg spot, not on the egg spot itself. (You can just see the egg spot in the second picture.

[babystarz]

I really don't know what it is, it looks like it could possibly be internal parasites but I'm not sure enough that it is to recommend you treat for it.

In the second picture, it almost looks like it's slightly see-through and possibly filled with fluid. Am I seeing that right or is that just the way the light is hitting it? There's a possibility that she is just really eggy and trying to expel the eggs.

[CLCDiver]

Originally Posted by babystarz

I really don't know what it is, it looks like it could possibly be internal parasites but I'm not sure enough that it is to recommend you treat for it.

In the second picture, it almost looks like it's slightly see-through and possibly filled with fluid. Am I seeing that right or is that just the way the light is hitting it? There's a possibility that she is just really eggy and trying to expel the eggs.

It is slightly see-through. And it shows a tendency to change in size and color. This morning it was larger than last night, with a pronounced red spot. This afternoon, it was larger still but the red was more diffused (the second set of pictures). Now it's smaller again, and more white-ish.

She's not looking plump, at least not to me, which is why I didn't jump right to suspecting that she's egg-bound, but I suppose it's possible. I don't have much experience with female bettas.

I just moved her to a smaller container with no substrate so I can see if and how she's pooping.

[CLCDiver]

*throws up hands in bewilderment*
And now it's gone! Completely gone. The amazing vanishing scary lump. I give up. I'll let you know if it comes back and/or I figure out what the heck is going on.

[aemaki09]

looks like a hernia almost!! and it looks like thats right where betta's poop from so I'd think it might be something wrong with her digestive tract? Maybe she over-ate or was constipated, and she has a hernia!? I know thats a really crazy, kind of out there in space idea, but its the only thing i can think of.