Can I resuscitate a drowned plant?

Can I resuscitate a drowned plant?

I received a Christmas cactus in December and it's been doing pretty well. It was putting out new branches almost daily and while it hadn't bloomed at all I attributed that to the fact that it's pretty warm here (coastal NC). Anyway, I recently read that they need indirect sunlight for best growth and as we don't really have anywhere near a window to set the plant without it receiving direct light, I put it out on my back porch last Monday once the sun was around the end of the house. Long story short, I forgot the plant outside and it poured rain that night. Now, over a week later, the soil is still damp (prior to this incident I'd had to water it once every three-four days) and now small, chalky looking spots have started showing up. They're white, about the size of a pencil eraser, and wipe away with just my finger. But then the next time I check the plant the spots are back. Any idea what the spots are? And, have I ruined my plant?
Plum & Avocado Tree Help..

Plum & Avocado Tree Help..

Photos and a question

Photos and a question

I made the best out of a rainy day

I made the best out of a rainy day

‘lo there.

‘lo there.

My Gardening Hat!

My Gardening Hat!

Macro – bis

Macro – bis