How long does the red bulls-eye symptom of lyme's disease rash last?

Days to months: Erythema migrans, the bulls-eye rash unique to lyme, appears within 3-30 days after a bite & lasts several days to several months. However, no more than 1/2 and probably less than 1/3 of those with lyme report a bulls-eye rash. If you have it you have lyme, but not having it does not rule out lyme in any way. See http://www.Lyme-disease-research-database.Com/lyme-disease-rash.Html.