I got this Senecio from Lowe's yesterday. Before buying it I noticed the brown spots, but I assumed it was soil stuck to the plant. I repotted it (50/50 mix of cactus soil and perlite, pot has drainage holes) yesterday and today I noticed one of the plants in the pot is falling over and the brown has gotten worse. It's hard to see in the picture but the leaves are also slightly wrinkled. Is it underwatering? Overwatering? Fungus? Any suggestions on what it is and how to fix it would be appreciated.