Water ceiling Ingress

[LucasJ]

Hi

I am looking for some advice regarding water ingress damage.

I have a 2003 auto trail Cheyenne.
Recently I noticed some blue water tide marks on the ceiling.
After a recent heavy down pour water found its water into our habitation
area through some cables coming out of the ceiling.

I had a repair place here in Portugal take a look at the roof,
they said looking at the ceiling it was most likely entering through a deteriorated
roof light (sun roof/skylight) seal.

They carried out a visual inspection of the roof and found the seal had
deteriorated. so they took the roof light out and replaced the seal..

I now am not sure what to do with the ceiling.
The blue tide marks are ok to look at as you hardly notice them.
But there is about 20cm square area that is spongy.

Now I must admit I was prodding this area a lot so that may have contributed to
it being spongy but it is certainly not has firm as the other areas.

I have also put a cheap damp meter on it and the readings are at
its highest 24%, this is lower than before repair 10 days ago.

Should I be worried about this?
will it dry out?
or do I need to cut the ceiling board out
to check if there is hidden damage?

Thanks in advance