Bald spot on head

Sockie

So today I just noticed a little bald spot on the corner of my head. I remember my twin sister having some bald spots when we were younger but mine were as little as hers. I don’t usually care what my hair looks like but this is really upsetting me and I just need some help. If any ladies have this please let me know what to do. I’m turning 22 tomorrow, and it’s the worst feeling ever.