Green’s Dictionary of Slang

(US, Western) one who is considered effeminate, a smartly presented city type.

1872		Schele De Vere Americanisms 225: A tow-head, originally nothing more than a light-haired boy [...] is not unfrequently applied to a city-man with store-clothes and carefully arranged hair, contrasting with the long matted locks which the backwoodsman generally affects.
1935		C.E. Mulford ‘Don’t Frame a Red Head’ in Western Fiction Monthly Aug. n.p.: I shore lost a wad playin’ faro-bank agin a tow-head.
1960		(con. WWII) R. Leckie Marines! 84: What, hell! A towhead?