Lymph nodes swell in reaction to all sorts of things. Worry when they're big and immovable and won't shrink back down, even then it might be nothing.
As for lyme disease, depends on where you live. I know a decent amount of central US states have zero reports of lyme disease and it's relatively uncommon on the West Coast. Keep an eye on it, maybe see a doc to be safe, specially if you're in an area (like Wisconsin) where they have a lot of Lyme Disease reports.