hi my dad has stage 4 throat cancer.it hit in the gums ,the tongue,and where your tongue meets your throat.it has hit all the lymphnodes above the neck.with grim statistics, my dad opted for combined radiation and chemo.he finished all treatments 3 and1/2 weeks ago.just a few days ago his tongue turned black.also in the back it looks like some type of growth because the sufrace of the tongue is lifted up and he can no longer stick out his tongue.he also has white dots and patches in his mouth.any thoughts?