The moral - don't poke!

Having had one disaster and found deteriorated damp plasterboard to one side of a partition (!?!) which will have to be cut out and replaced I decided to begin work on the last room being the kitchen.
I knew some was off key but should never have given it a poke! Now I have yet more plastering to do!
However I'm wondering if I can nick S for a half day as he's working on J's render/pointing next week and I'm sure it would not take him long to chuck a coat of hardwall/finishing plaster over this relatively small area.
Wonder if J will notice that he's skived off to me for a bit.........!