The phrase you translated as “… in his bald-spot or in his receding forehead”, is here translated by the Targum translates this as “… in his new garment, or in his worn garment”. The Hebrew words here are, however, identical to the words used earlier in the text for bald-spot & receding forehead. Whether these words are homonyms used for effect, or whether this is a context-sensitive idiom, or whether this is a textual error are purely speculation.