Hi bishop1980,
Did the doctor order bood work on your husband? At this point you need to have him seen by an immunologist, whatever bit him is affecting his immune system and this could be a problem futher down the road. Also contact your local exterminator (pest control company like Orkin) there should be several depending on where you live. These guys do this for a living, they may be able to help you narrow down the kind of pest that attacked your husband...did you by chance take a picture of your husband's injury with a cell phone? That would be of great help if you did. If not, start taking a picture of your husband, symptoms, swelling, blistering, etc from this point on and if you can note the incident surrounding it, for example, overnight, while walking, eating, sleeping, you want to notice if it is a pattern to the outbreaks.
Good Luck,
Faded Rose