I am not from TX, but even here, our weather this Spring has been extended cool down. Only this weekend did we finally return to our more seasonable warmer temps, but got too hot quick..oh well.
My Plumerias are not yet awake either..so will just wait for it patiently. That is something I have learned in all through the years, always something different every season each year.
As long as the rest of your plant is staying firm, no soggy part, then it is still okay. Just remove rotted new growth if possible, so it can heal that area properly. Still early in the season, it can still catch up. There was a time my Plumies finally made better leaves already towards June.
In the meantime, no watering, wait it out as patiently as you can.
