What do I do, my child is not eating anything whatsoever...?

What do I do? my son hasn't eaten anything for 7days already, he doesn't want to eat anything, ever since he went for a flouride treatment at school, He's scared to eat anything at all ! he doesn't want to put anything in his mouth. i am so worried about him, the only thing he eats is ice cream and jello and apple juice things that are not chewable. i'm scared for him to get sick from not eating. Is there anything I can do..