Has anyone grown Lithops (living stones) ?

I use to grow lithops myself and I think yours got too wet, they prefer the soil to be on the dry side. Keep them inside for now, put the bowl in front of the window and only put them outside when the sun is shining and get them in at night. Another problem could be the soil, cactus soil is not suitable for lithops, there is too much turf in cactus soil and lithops absolutely hate that. So try to find a compost with a minimum of turf and your plants will absolutely enjoy it and hopefully look a lot better soon :)