I have developed a dent on top of my eyebrow. Why has this happened and how can I fix it? (Photos)

I have developed a dent (not sure what to call it), on top of one of my eyebrow. I can feel it when I raise my eyebrow like the first pic, while the second pic my eyebrows are relaxed but it’s noticeable and looks weird. It randomly raises by itself sometimes. I’m not sure if this is some sort of muscles causing this, but if anyone knows how this can be fixed i would rly appreciate it :)