Hi @maine There have been numerous studies by researchers over the past decades of longterm side effects of Lyme disease. You can do an online search by typing in questions such as "Is there a link between Lyme disease and Cancer". You'll bring up a list of articles.

At this time, research results suggests Lyme disease does not directly cause cancer. However, chronic underlying inflammation, a potential consequence of untreated or persistent Lyme disease, is a known risk factor for various cancers including lymphoma.

Here's a smattering of some of the articles online. While I'm not advocating them as credible sources there is information of the possibility of correlation.

~Lyme Disease And Blood Cancer: A Startling Connection Revealed In New Study (tickbootcamp.com)
https://tickbootcamp.com/lyme-disease-and-blood-cancer-a-startling-connection-revealed-in-new-study/
~Does Lyme disease cause cancer. (advancestudy.org)
https://advancestudy.org/does-lyme-disease-cause-cancer/
~Can Lyme disease cause leukemia (medicalnewstoday.com)
https://www.medicalnewstoday.com/articles/can-lyme-disease-cause-leukemia
From what I'm reading, there's been no direct link with PV (polycythemia vera) or other myeloproliferative neoplasm disorders. There are many other random factors that can impact our bone marrow causing a misfire in DNA that can eventually lead a blood caner or chronic condition. You may never know the cause of your JAK2 mutation but I thought the point that @jammy17 brought up about Lyme disease and their MF diagnosis was interesting. So that's why I did a little sleuthing.