Hi, thanks for your query. I understand your concern for your skin condition. I shall try to solve your query. The exact cause of lichen planus is not known. Some consider it to be autoimmune phenomenon that is the body s immune system reacts to own cells as foreign. However certain triggers for lichen planus are known like certain medications like thiazide diuretics, antimalarials and phenothiazines. It is also related to liver disease or hepatitis C Heat rash is not related to lichen planus. There is no cure but the condition is self limiting. It may last from a few months to several years and spontaneously clear on its own. Till then you need to continue symptomatic treatment in the form of topical steroids, retenoids, avoiding triggering factors. Hope this solves your query. Wish you a speedy recovery