I'm 20 and I used to straighten my hair very often without using a heat protectant. I neglected oiling it and even brushing. I noticed the scalp (crown) became scantier in the part where I had my bangs/fringe as I used to straighten it excessively. however, I stopped straightening ever since . It's been a year and it is still scanty. But I'm taking care of my hair now. Can I start straightening? This time, spraying a heat protectant and taking care of it? I now oil my hair (almond/olive) and wash it thrice a week with a herbal powder. I'm from India.
Damage from straightening occurs along the hair and at the ends. When you say the crown is "scantier" do you mean that your hair is thinning on your scalp? That doesn't sound like a sign of heat damage.
It COULD be a type of hair lose that's caused by pulling on the hair (some straightening techniques require pulling on the hair a lot.) This kind of hair loss is called "traction alopecia."
I'm not sure if that's what you're experiencing or if something else is causing the problem.