text: not a doctor, but I guess that the teeth is like the feeling you get when your leg falls asleep and then blood rushed in and it feels weird.  As an adult it sucks, but as a kid it felt cool!  I think the nerve in the mouth is shallow and the and the antitussive is numbing them and the sensation she feels is feeling coming back.  Second the chest could be the same thing.  It probably the flem in the esophagus sliding back in to the lungs tickling the hairs/fimbrea that normally sweep up toward the mouth.  Or it could be an allergic reaction.  I get that same "tickling" when I eat a certain type of salsa.  I think its the preservatives.\nI am all about the herbals, but I'd rather try over the counter if my kid is having a reaction to herbal meds.