I Found a Bald Spot in the Back of My Head (with Photo)

I am 24, male. And found this bald spot a few days ago and getting really worried and dont know why or how it’s there. I would like help and advice if possible please thanks.

Click the photo to enlarge:

You should see a dermatologist. There are many conditions that can cause such a bald spot, including alopecia areata, fungal infection, allergy, injury, stress, etc. Is the spot growing in size since you first noticed it?