This is the way of natural materials sometimes... I'd first try tuning higher to see if you arrive at playable action at a higher pitch. If you trade buzzing from too much backbow for buzzing here and there around the neck, then you probably should think about having a fret mill. Even if the neck is bowed the wrong way with your preferred strings at pitch, this may be correctable in the fret tops if you have enough height.
If there's still too much back bow to do it in the fret tops, then you have a full refret where they can level the fingerboard when the frets are off. If the back bow is really bad, then the fingerboard may be visibly thinner in the middle, but this should correct the problem fully.
You need to consider the heat treatement only if the refret and fingerboard levelling won't fix it. Doing the heat treatment (steam heating the neck to loosen the glue joint between the fingerboard and neck) will require refretting and refinishing.
Good luck.
I'm originally from Ames, just north of you. Considerably more humid - that's putting it very kindly!
