Oh Mike first I am stunned like you and the rest of us here. I agree with Yorkiemother as she gave excellent advice. I, too, am worrierd about therapy visits now. I would believe that if you told them that Eddie bit you regardless of the circumstance that they would have to reevaluate him being a therapy dog. I am at a loss on this one..my heart would say don't tell that this truly was an isolated incident. I would try crating him at night and putting away the toys if that is a problem. Give it time..don't jump to anything yet with Delta.
Are you sure he is just not feeling right with all that he has been through with the foxtail incident? I would also talk to your vet on this one.