Hi.. Welcome to HEALTHCARE MAGIC... I have gone through your query and can understand your concern... As per your complain as you have been prescribed with Acyclovir which is an antiviral drug it is possible that the doctor must have diagnosed you with Herpes virus 1 infection which causes cold sores in mouth and can be preceeded with burning sensation before the sores appear in mouth. At times there is also cold like symptoms.. The symptoms like shakiness, confused and unable to keep the balance are all due to adverse reaction of the drug and stopping the drug is the correct decision and you should also take anti histamines or anti allergic like Allegra or Benadryl or Claritin for faster resolution of allergy symptoms and immediately consult an Emrgency room.. For burning of mouth My suggestion is to consult an Oral Physician and get evaluated for other possible conditions like Burning Mouth Syndrome or Apthous ulcers so that you get proper medication for relief.. As of now suck on ice pops and do cold water gargles for relief from burning.. If there is mouth pain also you can take Ibuprofen [Advil or Motrin].. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..