Without the sweating, bad breath, chills, pus, drooling, etc. it's hard to believe it could be Merc.

Rhust tox is indicated from exposure to cold/damp, plus it's better for hot drinks; so my inclination would be to move in that direction.
I believe that Merc. wants cold drinks, so, that's another reason Merc. might not work for you.

Snoopy