Hello and welcome to the forum. Sorry you are having that sensation. That's probably irritating! We encourage you to speak to your doctor about it. While it 'could' be associated with an autoimmune disorder, those typically cause rashes or tingling of the skin rather than what you describe. This article may help you with other ideas. https://www.healthline.com/health/formication Formication is the feeling of bugs crawling on your skin as the only symptom. Here's a list of things that can cause this:
herpes zoster (shingles)
skin cancer, such as cutaneous squamous cell carcinoma
So, on that list, some do feel fibromyalgia is caused by the autoimmune system although there is not a full consensus on this. And in the late stages of lyme disease, it has some autoimmune complexities.
Are you under a lot of stress lately?