Plastering above skirting - DIY or Pro?

Hi

I am new to DIY, just bought my first home (a reasonably well maintained Victorian cottage). We are addressing a room at a time and currently on a 9sqm bedrroom. I've replaced a bunch of floorboards and pulled of the skirting board with the intention of having exposed boards in the room.

Where i have removed the skirting, areas of the plaster behind have been damaged and areas have bubbled away from the brickwork. I am considering replastering these areas myself and have a few questions:

1. Should I do it or get a pro?

1. Should i go right to the boarding or where the plaster currently ends (above the original skirting). The new skirting is to be higher than the original.

2. There is a plug that was originally above the skirting, i want to sink this into the wall, should i do this in the skirting area or above it, what's the best practice?

Thanks for any ideas.

Blu.