I didn't have a rash, nor did my daughter -- at least, we never saw a rash, but it can be on the scalp and not seen. The rash seems to vary widely in different people, so I don't know that there is any rule of thumb ... but I would say it probably won't last very long.
"The rash can last anywhere from several days to several months, even over a year. It can come and go in cycles that are related to the treatment the Lyme’s patient is receiving. Treatment often causes something called the Herxheimer reaction, a presentation or relapse of symptoms."
This article is more conservative:
I, personally, have never heard of an EM lasting over a year---- but perhaps it does.
I never had a rash either.
Thanks so much.
Also in another thread thx for the info on Cipro kidney stones!