BigJohn, we don't know – she woke with it after a night in the grass/tent but only realised after we had packed away etc – didn't even think it might have been a tick bite etc until she read a leaflet later in the day – the steroid cream didn't help at all, but she developed no further symptoms so one would assume not, but she was never tested for it.
I think the concern comes not from her diagnosis, but their unwillingness to take it seriously because they never saw the bullseye rash, they seemed to assume we were making it up. The fact that they couldn't actually decide what had caused the thing made it even more concerning -"it's probably nothing" and a bit of generic cream is always worrying.