The muscles above my eyebrows bulge and form a V-shape - what is this? What can I do? (Photo)

My concern isn't forehead wrinkles, but muscles. I'm a 34 year-old woman who, in the past couple of years, has noticed that the muscles starting at the inner corner of her eyebrows are bulging. The two bulging muscles form a V-shape. I'm a frequent squinter and left eyebrow-raiser; in fact, the condition is worse on the left side of my face. I've never had any sort of cosmetic treatment, nor have I ever seen anyone else with this issue and can't find anything on the internet describing it. Help!