Sunburnt leaves do not heal. Plants can recover, but the damaged leaves will remain damaged. It's also possible that the ferts were too much. Once a week seems reasonable, but the ferts can build up in the soil, especially in small cups if you don't also flush some out with plain water.
Good luck!
I have a few more smaller plants if you want also. Let me know.
Good luck!
I have a few more smaller plants if you want also. Let me know.