Longest possible timespan between bite and EM rash?

Here's a fragment from a post I recently saw on someone's blog:

02/14/15
"My son was infected May 2014. He had his wisdom teeth extracted a week ago; the very next day he had three bulls eyes."

WOW. This would mean that stress alone was enough to create bulls-eye rashes from an earlier infection. This contradicts what I've been told about rashes always appearing within 30 days of a bite. It certainly makes me wonder: My bulls-eye appeared a week after I got mowed down by bed bugs (or whatever left 20 welts on me in that hotel room). Could it be that my immune response to all those bites brought Lyme to the surface that I've had for awhile? (Though no other symptoms besides rash.) I'm doubting it, but that guy's post is scary. What do you think?