I do a RO water and iodine dip on every frag or colony that is going into my tank.
Not that it is a cure all, but it helps to rid the frags of most types of pests.
They could still open up and be just fine. Sometimes it takes a few days to open, sometimes a week or so. As long as they are not "melting" or showing anything bad, they should be OK.
I had a frag go into my tank last Saturday, and it took until yesterday to even see one polyp open. Today almost all are open.
Give it a little time and see.