Without knowing the temperatures that you were dealing with for the 3.5 weeks I can't give a definitive answer. If the temperature around the deer held at less than 28 degrees, which would result in the meat being frozen the whole time, it should be ok.
    However if the temperature fluctuated above and below 28 (the point at which meat freezes) but stayed below forty then it may still be ok, but any exposed meat will be dried out and have to be trimmed away. (Having the hide on is a plus to prevent it from drying out.)
    If temperatures climbed above 40 for any length of time then I would guess it is definitely bad. You should notice mold in the cavity.
    As far as the tongue, that is going to happen because it is exposed to the air and dries out.

Dave