Acording to the legend of Tarzan he at some point realized he was very different from his ape bretheren - some versions have him seeing jungle villagers or even white hunters. Anyhow, realizing his vast difference he was determined to embrace his difference and taught himself to scrape hair from his face with sharpened stone or bone. Later he was discivered and returned to civilization where he found out he was actually Lord Greystoke, a British peer and lived that life for a time before voluntarily returning to the jungle and his animal family.
Real Tarzan does have facials 3 feet long. I met him in person. It took an experienced team of make up artists about 17 hours to make him look presentable in the movie. I have to add he couldn't stop looking at himself in the mirror. And since then and because he admires himself so much, jane had been calling him an ignorant bastrd. Hope this helps.
He saw pictures of 'man' in books (that his deceased parents had on the island) ... made the connection that he was not ape, but man & used a pocket knife he found in his parent's cabin to shave his beard. He wanted to distinguish himself from the apes.