what grade of thinner did you use in the lacquer? or are you using spray cans?
i suggest you wet sand the surface, until it is nice and smooth, with either the 600 or 800 whichever you know is wet/dry paper. then let the body sit in the sun for a couple of days. then start over with the white base coat.
how many coats of clear did you use? did you allow the proper flash time between coats?
make sure to avoid what we used to call "the thicker is quicker" method when applying lacquer because you can end up trapping solvents in the first coats of clear. always use the correct grade of thinner, the correct reduction % and the correct application method. more coats applied correctly will always work better than trying to spray fewer really wet coats.
your picture looks to me like you applied the white base coat in very heavy coats and you didn't give it enough time in between coats. then you sprayed the clear in the same method. this traps a lot of solvent/thinner in the finish and it can cause a problem exactly like what you are going through. everything looks great until you start wet sanding. then you expose the layers of paint ruined by the excessive solvents.
yes, waiting three weeks before wet sanding and wheeling is a way of doing things but in the real world this is seldom possible. we would shoot lacquer on a cadillac and sometimes buff it the same day, at the most it would sit until the next day but very rarely. did we have die-back? yes, after a week or two a customer would notice a few spots that didn't shine as well as they should. a little rebuffing and they were good to go. that was the accepted method for thirty plus years and it still is today.
with a guitar body you can give it more time than a cadillac hood in a production bodyshop.
proper application is the key, "thicker is quicker" is usually not quicker in the end. once you get the application correct place the body someplace warm, with fresh air, for a couple of days then start the wet sanding and polishing.
