Parashas Metzora · Passuk 14:18
Chabad.org — English translation + Rashi
Torah Temima points to Yoma 61a (verified on the daf).
E-Daf.com — Tsurras Hadaf (size=3)
HebrewBooks / Shas PDF of the daf
English: “And the remainder of the oil …” — if the priestly placements [on the ear, thumb and toe] have been completed and the log is then spilled, all agree that the placements on the head do not hinder [the validity]. Why? Because it is written “and from the remainder of the oil” and “the remainder of the oil he shall place on the head of the one being purified.”
Non-essential status of the head placement
Chazal teach that once the three primary placements have been performed, the subsequent placement of the remaining oil on the head is not indispensable.