white tongue

i have a lot of allergies (only airborne that i know of) and i get a lot of sinus infections. in fact i think that one of my sinuses over my right eye actually busted once..if that's possible? it was hurting so i rubbed it and it popped!! so anyway..my tongue is white..i did have a very bad sinus infection..but i have seen my dr. about the white tongue and am taking my second round of antibiotics to get rid of all the sinus buildup. she tested for thrush and it's not..my blood work came back good..blood count..kidneys..liver..but my tongue stays white and will not go back to normal. and my tongue is soooooo dry!! i cant keep it from feeling like its drying out. very uncomfortable! so is this allergies..or thyroid..or something wrong w/ my tongue or neck?? seriously..i need some answers..please..im freaking out!!! the antibiotics r not making it any better :(