The symptoms of a typical migraine attack may be severe and alarming, but in most cases there are no lasting health effects when the attack ends.
However, a change in the pattern of headache (such as an increase in attack frequency or severity) or onset of a different kind of headache can be a “red flag,” meaning it could be a sign of a more serious underlying condition. Red flags include headaches that occur with infection (which may be accompanied by fever, chills, night sweats, or muscle pain) or new headaches that develop in the setting of cancer, weight loss, or pregnancy. Other concerning symptoms include headaches associated with confusion, double vision, ringing in the ears, a stiff neck, or weakness on one side of the body. If you have any of these “red flags,” tell your health care provider right away or seek emergency care.
–Alice Wong, NP
https://www.uptodate.com/contents/migraines-in-adults-beyond-the-basics