Damaged Plasterboard Behind Skirting

[mrsparks]

I've recently removed the skirting in the living room so that we can lay new flooring (properly) and new skirting on top. The old skirting was a right pig to remove, held by those hammerhead nails into dot and dab walls. Suffice to say, removing the old skirting has resulted in a lot of damage to the plasterboard behind. Now I realise it won't be seen once the new skirting is in place but I thought I should make an effort to patch it up somehow so that the new skirting has something reasonably flat to butt upto.

There are a number of areas where the surface paper on the plasterboard has come loose on its bottom edge - it's still attached but it's flapping about. The gypsum behind is sound though. Should I just stick the surface paper back somehow - and if so, with what? (I know the new skirting will be glued with something, but if the paper face isn't secure neither will the skirting be. I expect it'll be pinned as well though).

There is one part where a whole dot/dab of adhesive has come away - pulling one of those nails out has pulled a whole dot/dab with it. Can I just stick that back in place using squirty foam adhesive or something? Otherwise there is going to be quite a void behind the skirting in that area.

There's lots of areas where the pry bar has squashed the plasterboard. I don't suppose there's much I can do about those.

[wine~o]

Jusy slap some filler in there, do not use expanding foam. maybe a little piece of wood of the appropriate size glued /screwed in place.