How do you turn your mermaid sim back into a human?

i found that if you eat ANOTHER MERMAID KELP and DON'T GO into the water you TURN BACK INTO A HUMAN!!!

i haven’t left my house in days and still a mermaid. 

@whynotuh  The idea is that your mermaid needs to dry out, so to speak, to turn back into a human.  So if you're letting the sim rehydrate, he or she will stay a mermaid indefinitely.