Hello. For the past 6 months, I get a u shaped vein that sticks out on the upper right side of my forehead. The strange thing, is it comes out for a few days, then goes away for a few weeks. I havent seen it for a few weeks now, then starting yesterday, it is sticking out again. What could this be? It does not happen right after exercise or anything obvious. It is very spontaneous. I am a 46 year old female. Could it be change in hormones? I also get migraines once a month, but have found no correlation between the time the vein pops out and a migraine headache. Thank you.