Viewing post #3059578 by DrawingMoo

Brought this philodendron (pretty sure it's a Black Cardinal) home earlier this past week and it wasn't wilting, but it was bone dry, so I gave it a little water (slightly warm as per instructions, and had been sitting out). It still seemed pretty dry a few days on and still wilting (As of this morning, began developing black stripes/patches with yellow edges) so I gave it some more water earlier today. It continues to get worse.

I'm worried if I should repot it into a mix with some perlite since the soil from the store seems very loamy, or if I overwatered it, or if this is a fungal infection and I should be cutting these leaves before they spread to the plant. If I overwatered it, can I just let it be to dry out or should I repot it into a dry mix, the sooner the better? I really don't want to lose this guy, never cared for one of these before, but I'm at a loss for what to do. Please help me identify this and if you have any solutions, I am welcome to them.