Overwater?

i would give her another growpot and some fresh soil underneath....

I will get on my soapbox for a little bit here. No offense intended. I always stress the use of fabric pots when growing indoors. In fact some major LED makers highly recommend using them, as LEDs run cooler, keeping soils moist longer. Not sure what your light setup is, so the above may not apply to you, but even with hotter HPS/HID lights, fabric pots help keep you from hurting yourself. The bottom and sides shed water better, and help keep your roots from drowning and "air trims" roots, to keep them from binding up. With these, I use the two knuckle approach, in the soil. When it is cool, but not damp, flood the pot until you see water collecting in your drip area. The pot will drain optimally, and will dry out consistently, every 3-4 days (3 gal pots), depending on temps, circulation and size. An added bonus, it will assist in providing a little extra humidity depending on your grow space. Only downside, you go through more water on a given grow. Good luck on that recovery!!

Mate , remember the roots will have took a big hit too. maybe introduce some benefials to the soil to sort the dead roots if any , they will mulch them to food. Water a little and often until you can establish a water cycle and table again. Try watering in a spiral from stem to outer edge to encourage new roots to get busy.

Hello, depends on the temperature of your grow environment? what is the temperature with the light on? your leaves seem to be showing signs of too much heat. it could be a root problem and PH variations. try to establish the PH of the Solo at 6 and give it a root stimulator for them to gain strength. ventilate your plant well with a fan blowing directly at it. good luck 🙏🍀🌱