The plural headhairs is used when referring to more than one individual strands of hair on or from the head.
From Middle English *heed-heer, from Old English hēafodhǣr (“hair of the head, headhair”), equivalent to head + hair. Cognate with Dutchhoofdhaar (“headhair”), GermanHaupthaar (“headhair”), Danishhovedhår (“headhair”), Swedishhuvudhår (“headhair”).
English Wiktionary. Available under CC-BY-SA license.