Fandaniel frowns, wrestling with what passes as his conscience. Clearly Tidus just wants to help, and he could just.. lie .. but that could be inconvenient later, like if he seriously needed healing and everyone was worried about not saving him because it might hurt.

"It won't kill me," he says after a mighty struggle with his own sense of right and wrong, "It's just unpleasant."

Which is to say it's perfectly fine, what healing ISN'T unpleasant? "Unless you start with the light beams and such, those certainly hurt a lot."