i developed a bald spot virtually overnight, why? (photo)

It would be unlikely the bald spot appeared almost overnight.  You may want to see a doctor for an examination to find the diagnosis.

This needs formal evalation fortypes of hiar loss, sudden loss could be alopecia areata.  Best, dr emer

Based on your brief history of “overnight” hair loss in a small limited area of your scalp the most likely diagnosis is alopecia areata, an auto immune disorder.  Alopecia areata can be treated with topical or subcutaneous injections of corticosteroids.  Hair transplant is not advisable into the area of alopecia areata. As long as the active disease is still present, transplanted hairs will succumb to the same fate as the hairs that were originally in the area.

If you truly developed a bald spot overnight, there is only one diagnosis - alopecia areata. Nevertheless, it's important to see a physician for an up close examination.It is not uncommon for patients to have a spot of hair loss that goes unnoticed for a long time. However, a spot that develops overnight is only one diagnosis - alopecia areata.

I consider important that you visit a dermatologist and based on the diagnosis consider visiting a Hair Specialist Doctor to explore the different treatments that can help you get rid of that bald spot.As mentioned before, maybe you didn't noticed that bald spot before and now it just enlarged. It could also be something that your dermatologist can make regrow with a medical treatment.Best of lucks!

You need to be seen by a hair restoration specialist.  If your hair loss is caused by genetic male pattern hair loss then hair transplant is a great option, you can also start on a medical hair regiment routine to slow down future hair loss.

You probably did not notice the bald spot before. It must be examined by a doctor to find out what is the cause of the bald area. 

You probably has Alopecia Areata which has a very high regrowth rate.  See a Dermatologist as soon as you can and it can be appropriately treated .