What Causes Stinging Sensation In Lips After Drinking Something?

hi i know a late 50 year old who is diabetic and suffers from bp (but is being slightly controlled by tablets). This lady suddenly felt numbness on her right arm and leg, her GP suggested its a trap nerve? she id due to have a blood test, but i have noticed that she is actually dribbling sometimes and she has said that when she drinks something her right side lips sting? would could all this mean? thank you