I found a couple bits of information for you on the internet. I did see other people mention that family members have reverse fevers or that they have a normally low body temperature, but they were mentioned as asides rather than a diagnosis. Below is a chart that explains the normal temperature range according to where on the body the temperature was taken.
Rectal: 97.9F - 100.4F, Fever >100.4F
Oral: 95.9F - 99.5F. Fever >99.7F
Axillary (under arm): 94.5F - 99.2F, Fever >99.3F
Tympanic (Ear): 96.3F - 99.9F, Fever >100F
The second is a question someone asked online and a response. Don't know the qualifications of the responder, so don't know how much value to assign to the answer: http://www.justanswer.com/questions/1eg7r-is-there-such-a...
To help narrow the search, I googled:
"reverse fever" -hypothermia -blister
Using quotes around your search words indicates that they should be listed next to each other, not just in the same sentence or page randomly.
The - sign before a word indicates that the word should be eliminated from the search results. Now you won't have to sift through all the hypothermia and fever blister sites.
Good luck. I hope this helps.