Problem with leak/damp

During the month of November we had a burst water pipe just outside the house.  This was undetected for a few weeks by which time we had lost 234 cubic meters of water mostly under the house.  The pipe was repaired and, at the time there appeared to be no permanent damage.  However some five months later we are now seeing loose plaster and dampness in one of the rooms, all at floor level.  A ‘damp’ meter is showing an extremely high damp reading.  Is this something that will dry out in time or should we seek professional help?  And is the reason it has taken so long to show any problems due to the warmer weather and the drying out process?

Any advice greatly app