I have had teeth extracted,the last one was taken out in July.when I finish taking the antibiotic I developed a pealing of the skin in my mouth,I went to the doctors and he thougth it was thrush.Took meds that were prescribe,did not help.Been back 2 more time ,prescribe the same drug for the second time and a mouth wash for the last time.My mouth is not shedding skin anymore but my lower lip is sore,dry and burning.what could it be ?