Fertilizer burn maybe?

No - I haven't give it any fertilizer yet. Just water.

The rolled edges can be caused by pests and the front leaf on the 2nd pic has some yellowish spots to it appears. Check for aphids or spider mites.

Probably aphids or mites.
I would remove it and examine it closely with a magnifying glass .

Seysonn

I checked carefully. I don't have aphids, mites, or any other bugs. The yellow spots are from edema (I watered too much) —The back of the leaves swell up and caused the discolored indentations on the other side. The situation has gotten worse. One other leave is completely shriveled up, so I pulled it and the other as well.

I'm going to transplant both plants into bigger pots tomorrow. Hopefully, the new medium will help.

The top leaves are rubbery, as if I wasn't watering it enough, which isn't true—So, the problem is that something is preventing the roots from transporting the water to the leaves. I transplanted it into a much bigger pot, mixed in a half-dose of Tomato-Tone fertilizer and gave it a good soaking.

I was thinking too much water? Are you letting them dry between waterings?

Let's see if it gets worse after soaking.....Good luck!

I may not have let them get dry enough between waterings. The problem with potting soil in clay pots under lights is the top few inches of the soil gets dry quickly, but I'm not sure about the rest of the soil. As the pots are so light anyway, it is hard to judge by weight, whether they need watering. Hopefully I didn't make it any worse by soaking :) We'll soon see.

too much moisture (Leaf Odema) is also the cause of leaf rolling and curling. Some varieties are more sensitive to over watering. . another cause can be too much Nitrogen.
What kind of potting soil are you using ?

Seysonn

From the label of my soil:

This product is a blend of peat, Canadian Sphagnum peat moss, perlite, compost, dolomite, lime and wetting agent.

Not familiar with your soil or know the percentage of ingredients but would be concerned about moisture and water needs. Share pic of bag if you can. Also, clay pots are heavier probably making it trickier to see what's going on at the bottom. When using plastic, i could easily tell if water was needed by just picking them up. Was the soil soggy or show signs of wet feet when transplanted? Any root discoloration? Won't hurt to let them dry up a little....