There is not much that can you do at this time. This kind of symptom has been observed on many coconut palms this spring and early summer. If new fronds continue to emerge the palm may eventually produce normal fronds and survive. However, some cold-damaged coconut palms have produced new growth and appeared to be recovering but later died due to secondary trunk rot diseases. Only time will tell whether your coconut palm will survive.

See also the attached article from the University of Florida for more information.