?Herpes zoster Its a reactivation  of Varicella -zoster (VZV) that has a dormant within the dorsal root ganglion, often for decades after exposure to the virus in the form of varicella(chicken pox), results in herpeszoster. Neuritic pain, vesicles(fluid filled lesions) on redbase,fever..etc   usually unilaterally its classical presentation... stress, lack of sleep,excessive travel..immunosuppression or immunodefiency...etc will precipitate. Chronic phase results in POST HERPETIC NEIRALGIA(PHN), more often this neuritic pain caused by damage of nerves by virus specifically elderly patients and immunosuppressive patients suffers more, starts after 4 weeks may last up to 18 months or sometimes.