Hey everyone, I'd greatly, greatly appreciate any advice anyone could give me on a situation that's worrying the heck out of me.

I live in a duplex with a stone exterior. Several months ago, the paint beneath the windowsill in my office room started bulging. At the time, we discovered that, on the other end, on the outside wall, the mortar between several stones had come loose and turned to dust, which I'd presumed was the cause of the bulge. We had the wall repaired in June. I've usually got my desk against the area where the bulge is, so it's not an area I regularly see, and I was planning on plastering and re-painting the space at the end of the summer.

I'm currently two days away from leaving for a business trip and to my horror, I looked at the area and discovered that the bulging got significantly worse, has spread, and is cracked in several places. Attaching a photo to illustrate.

Touching inside the exposed places, it feels very slightly (almost subliminally) damp. If I pull gently on any of the cracked pieces, I can easily move a portion of the painted surface, which seems to have separated from the wall. What on earth could be causing this?

My immediate worry is that I could smell a subtle mould smell if I place my nose up by the cracks, and I live with an asthmatic cat. There's no visible mould, thankfully, and he's not shown any symptoms of sensitivity, but as I leave in two days, what can I do to prevent any dangerous levels of mould growth from happening while I'm gone? I'm almost temped to peel off the entire area, spray it with Clorox and then plaster it up a few hours later, just as a precaution. :(