Commentary for Nazir 55:9

Rav Sherevya raises an objection - can you infer that the mishna is referring to a short naziriteship? Doesn't it say "he starts counting immediately, and he does not negate the earlier [days]"? What kind of naziriteship could that be referring to? If we say [it is referring to] a short naziriteship of thirty days, can you say that it does not negate the earlier [days]?

Doesn't he require hair growth - after his shaving due to the leprosy? And he will not have that, because there is no "hair growth" in less than thirty days.