There are actually hairspring manipulation videos on YouTube, I am really surprised by this.
Past a certain type of bend, the hairspring is compromised and cannot be repaired to operate within parameters. They will break, so actual kinks mean it is a lost cause. The modulus of elasticity of the spring changes over many years, and the springs get 'rubbery' for lack of a better word. When you think the slow ones used to do 432,000 alternances per day times however many years the watch has run, you can see why.
A modern watch running at 4 Hz makes 691,200 alternances per day.
One thing I should mention is that older watches especially will suffer from magnetic fields. The hairspring will become magnetised, as will various steel parts in the movement. Before any measurement or adjustment is ever done on a movt, it is always demagnetised first. In today's world there are many sources of this, not the least being cell phones.
Keep cell phones well away from vintage watches. I wrote a blog about this: