Betta Fish: Female with Popeye

Hi guys, I just joined. For context, I'm 19, and this is my first Betta ever. My younger brother caught it at one of those awful children fish catching places, so since then I've been dedicating myself to making sure she has a comfortable life from now on. Her name is Helektra, I am not sure how old she is but I believe she's already an adult, and I love her very much. I have had her for a short time, I only got her about 2 weeks ago. I immediately bought her a bigger tank(15L, which I know is still not the minimum, I plan on getting a 5 gallon/19L soon I promise), live plants(java fern, red root floaters, micranthemum), a HOB filter, and a gravel pebble substrate.

So far she's been great, I feed her twice a day, morning and night, she approaches me when I get close to her tank, she seems to like all her plants, she has a floating Betta hide as well.

This morning(8am), I went to feed her breakfast, and she looked completely fine. However, when I checked up on her at 12pm, I saw her right eye had swollen a significant amount, her left eye was fine. I did research, I believe it is unilateral popeye and she just injured herself, and I immediately transferred her to a separate tank while I did a major water change.

It is now 4:15pm on the sam day as I write this.

While I hear it should heal on its own, I plan on getting kanaplex very soon just in case. If anyone has any tips, please please voice them out, I really care about her and want her to have the most comfortable life I can give her.

And also since I'm here for the first time and new to Betta fish caring, do also let me know what you can observe about her and identifications as I have no idea how to do that other than she's a female Betta fish lol 😭😭😭