Commentary for Kiddushin 71:5

The Talmud pushes the argument further. We could say that “Speak to the sons of Aaron” refers only to the first few verses and not to the prohibition of making a bald spot. And the gezerah shavah is needed for another baraita that teaches the rules governing this prohibition. [The gezerah shavah appears in the continuation]. The baraita teaches two rules. 1) One is liable for each bald spot. 2) The prohibition refers to the whole head, not just between the eyes, as is stated in Deuteronomy.