If anyone can help me find out what my sister has I would be most grateful. She has some sort of episodes that occur at random, there's no set pattern, where she feels as if her skin is on fire or as if acid has been thrown on her it burns to bad. It also burns terribly in her mouth, tongue, throat, gums, her entire body. The Dr.s can't seem to find anything and they don't know what's wrong. She said it is so bad sometimes she wants to call 911. She is also extremely tired, listless and weak. Can anyone help us or is this an unknown affliction????? My sister is at her wits end, it's been going on now for 1 year.