Is there any way I can save it? :(

I'm sure I over watered this guy. I'm new to lithops (and caring for any plants in general) and I don't know if I can save it.

I have two other lithops and they are doing OK, but this guy ended up being over watered somehow. I repotted all of them maybe 2-3 weeks ago with a succulent mix, mainly because my sister believed it was overwatered and might have had root rot (it didn't, but we had to make sure).

I tried my best to not give this one as much water as the others, but when I looked today, it was very mushy, sad, and the soil was soaked.

Is there any possibility I can save it???

I give a bit of water every Sunday, if I should change my watering habits, PLEASE LET ME KNOW.

I also use my sister's small grow light that she uses for her plants, I will eventually get the one we currently have and she will buy a bigger one for her plants.