Concerns about crown hair loss

Whenever I go to the hair salon, they always say I have thinning hair and sparse hair density at the crown.

I'm stressed because of this.

After researching about hair loss

If the hair follicles die, hair will not grow at all.

Hair follicles are alive, but due to various causes such as temporary stress, hair can become thinner.

Do I need to see a dermatologist to get diagnosed for hair loss?