I can easily see the shrink being asked by Dexter to help Deb get a grip again, since they both know what he is, and she is a psychologist. Deb needs some serious help, and who wouldn't after all that shiz.
I also see the shrink wanting to really get to know what makes Dexter tick, and helping him figure some things out....not sure she would turn him in..I think she's going to want to study why he is who he is and what his thought processes are.
I can see some officer figuring it out, and Dexter dying in a bloodbath, and she will say he really wasn't a bad guy, misunderstood perhaps.