We put 11 coats of very thin lacquer on our guitars and it is are rubbed down between coats so the finish very thin, this is to keep the body as free as possible to move and resonate, one of the reasons our guitars sound so good, no thick yacht varnish embalming procedures in our workshops.
Thin finishes like ours do have some draw-backs like being easier damaged than standard finishes.
It looks like you've got a hairline lacquer crack and the whiteness you're seeing is the separation of one of the lacquer layers. It's nothing to be concerned about and can be easily sorted but you need the right stuff to do it.
The easiest and quickest way requires thin runny super-glue not
the standard stuff, and a very steady hand and a needle.
Next you need some capillery action, this is very kindly provided for you, no need to go looking for it
Using the needle to dab small amounts of thin super-glue onto the crack will allow capillery action to take over and the super-glue should run into the lacquer layers almost instantly.
Super-glue is dangerous, only use it if you've done so before and be very careful not to get any on to other parts of the guitar, it dries fast and takes no prisoners .... if in any doubt take it to a proper guitar tech