Hello! I have been through your question. According your concern you should know that XELJANZ(Janus kinase inhibitor) can lower the ability of your immune system to fight infections and you may be at a higher risk of developing shingles, as you have now. Some people can have serious infections while taking XELJANZ including tuberculosis (TB), and infections caused by bacteria, fungi, or viruses that can spread throughout the body.Usually in the immunodeficient person (in your case casued from this drug) the shingles can be more severe and last more than usually. Antiviral drug (acyclovir or valacyclovir) may reduce the severity and duration of shingles but you must start as soon as possible. What I suggest usually to reduce complications in immunocompromised individuals with facial shingles is using intravenous acyclovir for 5-7 days and topical lotions ( soothing rash or blisters) and gabapentin (for postherpetic neuralgia) along antiretroviral and as well you should do physical examination by oculist and to talk with your reumatolog if you can stop or reduce the dose of Xeljanz. Related the hair loss you should know that the viral infection that causes shingles can result in hair loss through a condition known as cicatricial alopecia (or scarring alopecia). Scarring caused by the shingles rash destroys stem cells in hair follicles that create new hair growth. The destruction of these cells prevents hair regeneration, resulting in permanent hair loss. However, to prevent further hair loss you must avoid scratching and combing too hard. I hope my answer help you. I wish you a quick recovery.