You have a Class 4A pattern of balding with a persistent frontal forelock. The balding is behind the forelock and the forelock looks strong. Forelocks that persist after the age of 35 often stay and there is a strong family history in balding families with strong forelocks such that a man can lose almost all of his hair and still keep his forelock.  Since you reported that you are 42 years old, I think that is the case with you but I would need to examine your forelock to see just how permanent it is and see if there is any miniaturization in it. Weak forelocks show miniaturization, strong ones do not.  I would transplant the area around your forelock to complete the frontal hairline if your forelock is strong and also transplant the area behind the forelock as well.

Clkass 4A with PFF